HDAC11 Regulates Palmitate-induced NLRP3 Inflammasome Activation by Inducing YAP Expression in THP-1 Cells and PBMCs.

Histone deacetylase 11 (HDAC11) has been implicated in the pathogenesis of metabolic diseases characterized by chronic low-grade inflammation, such as obesity. However, the influence of HDAC11 on inflammation and the specific effect of HDAC11 on the palmitic acid (PA)-induced NLR family pyrin domain containing 3 (NLRP3) inflammasome activation are poorly understood. The effect of PA treatment on HDAC11 activity and the NLRP3 inflammasome was investigated in human peripheral blood mononuclear cells and THP-1 cells. The PA-induced responses of key markers of NLRP3 inflammasome activation, including NLRP3 gene expression, caspase-1 p10 activation, cleaved IL-1ß production, and extracellular IL-1ß release, were assessed as well. The role of HDAC11 was explored using a specific inhibitor of HDAC11 and by knockdown using small interfering (si)HDAC11 RNA. The relationship between HDAC11 and yes-associated protein (YAP) in the PA-induced NLRP3 inflammasome was investigated in THP-1 cells with HDAC11 or YAP knockdown. Following PA treatment, HDAC11 activity and protein levels increased significantly, concomitant with activation of the NLRP3 inflammasome. Notably, PA-induced the upregulation of NLRP3, caspase-1 p10 activation, the production of cleaved IL-1ß, and the release of IL-1ß into the extracellular space, all of which were attenuated by FT895 treatment and by HDAC11 knockdown. In THP-1 cells, PA induced the expression of YAP and its interaction with NLRP3, resulting in NLRP3 inflammasome activation, whereas both were inhibited by FT895 and siHDAC11 RNA. These findings demonstrate a pivotal role for HDAC11 in the PA-induced activation of the NLRP3 inflammasome. HDAC11 inhibition thus represents a promising therapeutic strategy for mitigating NLRP3 inflammasome-related inflammation in the context of obesity.

Lactoferrin-Anchored Tannylated Mesoporous Silica Nanomaterials-Induced Bone Fusion in a Rat Model of Lumbar Spinal Fusion.

Lactoferrin (LF) is a potent antiviral, anti-inflammatory, and antibacterial agent found in cow and human colostrum which acts as an osteogenic growth factor. This study aimed to investigate whether LF-anchored tannylated mesoporous silica nanomaterials (TA-MSN-LF) function as a bone fusion material in a rat model. In this study, we created TA-MSN-LF and measured the effects of low (1 µg) and high (100 µg) TA-MSN-LF concentrations in a spinal fusion animal model. Rats were assigned to four groups in this study: defect, MSN, TA-MSN-LF-low (1 µg/mL), and TA-MSN-LF-high (100 µg/mL). Eight weeks after surgery, a greater amount of radiological fusion was identified in the TA-MSN-LF groups than in the other groups. Hematoxylin and eosin staining showed that new bone fusion was induced in the TA-MSN-LF groups. Additionally, osteocalcin, a marker of bone formation, was detected by immunohistochemistry, and its intensity was induced in the TA-MSN-LF groups. The formation of new vessels was induced in the TA-MSN-LF-high group. We also confirmed an increase in the serum osteocalcin level and the mRNA expression of osteocalcin and osteopontin in the TA-MSN-LF groups. TA-MSN-LF showed effective bone fusion and angiogenesis in rats. We suggest that TA-MSN-LF is a potent material for spinal bone fusion.

Plk2-mediated phosphorylation and translocalization of Nrf2 activates anti-inflammation through p53/Plk2/p21cip1 signaling in acute kidney injury.

The Plk2 is a cellular stress-responsive factor that is induced in response to oxidative stress. However, the roles of Plk2 in acute kidney injury (AKI) have not been clarified. We previously found that Plk2 is an interacting factor of Nrf2 in response to cellular stress, since Plk2 is upregulated in the Nrf2-dependent network. Here, we show that the levels of p53, Plk2, p21cip1, and chromatin-bound Nrf2 were all upregulated in kidney tissues of mice or NRK52E cells treated with either cisplatin or methotrexate. Upregulation of Plk2 by p53 led to an increase of Nrf2 in both soluble and chromatin fractions in cisplatin-treated NRK52E cells. Consistently, depletion of Plk2 suppressed the levels of Nrf2. Of note, Plk2 directly phosphorylated Nrf2 at Ser40, which facilitated its interaction with p21cip1 and translocation into the nuclei for the activation of anti-oxidative and anti-inflammatory factors in response to AKI. Together, these findings suggest that Plk2 may serve as an anti-oxidative and anti-inflammatory regulator through the phosphorylation and activation of Nrf2 to protect kidney cells from kidney toxicants and that Plk2 and Nrf2 therefore work cooperatively for the protection and survival of kidney cells from harmful stresses.

Intrinsic and Extrinsic Transcriptional Profiles That Affect the Clinical Response to PD-1 Inhibitors in Patients with Non-Small Cell Lung Cancer.

Using a machine learning method, we investigated the intrinsic and extrinsic transcriptional profiles that affect the clinical response to PD-1 inhibitors in 57 patients with non-small cell lung cancer (NSCLC). Among the top 100 genes associated with the responsiveness to PD-1 inhibitors, the proportion of intrinsic genes in lung adenocarcinoma (LUAD) (69%) was higher than in NSCLC overall (36%) and lung squamous cell carcinoma (LUSC) (33%). The intrinsic gene signature of LUAD (mean area under the ROC curve (AUC) = 0.957 and mean accuracy = 0.9) had higher predictive power than either the intrinsic gene signature of NSCLC or LUSC or the extrinsic gene signature of NSCLC, LUAD, or LUSC. The high intrinsic gene signature group had a high overall survival rate in LUAD (p = 0.034). When we performed a pathway enrichment analysis, the cell cycle and cellular senescence pathways were related to the upregulation of intrinsic genes in LUAD. The intrinsic signature of LUAD also showed a positive correlation with other immune checkpoint targets, including CD274, LAG3, and PDCD1LG2 (Spearman correlation coefficient > 0.25). PD-1 inhibitor-related intrinsic gene patterns differed significantly between LUAD and LUSC and may be a particularly useful biomarker in LUAD.

Histamine causes an imbalance between pro-angiogenic and anti-angiogenic factors in the retinal pigment epithelium of diabetic retina via H4 receptor/p38 MAPK axis.

INTRODUCTION: Systemic histaminergic activity is elevated in patients with diabetes mellitus. There are a few studies suggesting that histamine is implicated in the pathogenesis of diabetes, but the exact role of histamine in the development of diabetic retinopathy is unclear. The aim of this study was to investigate the role of histamine receptor H4 (HRH4) in the regulation of retinal pigment epithelium (RPE)-derived pro-angiogenic and anti-angiogenic factors under diabetic conditions. RESEARCH DESIGN AND METHODS: The levels of vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), histamine and histidine decarboxylase (HDC) in the serum and vitreous samples of patients with diabetes were compared with those of patients without diabetes. The effect of hyperglycemia on expression levels of HRH4, VEGF, IL-6 and pigment epithelium-derived factor (PEDF) in the RPE was determined. The role of HRH4 in high glucose-induced regulation of VEGF, IL-6 and PEDF in ARPE-19 cells and the underlying regulatory mechanism were verified using an RNA interference-mediated knockdown study. RESULTS: The serum and vitreous levels of VEGF, IL-6, histamine and HDC were more increased in patients with diabetic retinopathy than in patients without diabetes. HRH4 was overexpressed in RPE both in vitro and in vivo. Histamine treatment upregulated VEGF and IL-6 and downregulated PEDF expression in ARPE-19 cells cultivated under hyperglycemic conditions. Hyperglycemia-induced phosphorylation of p38 and subsequent upregulation of VEGF and IL-6 and downregulation of PEDF were dampened by small interfering RNA-mediated knockdown of HRH4 in ARPE-19 cells. CONCLUSIONS: Taken together, HRH4 was a critical regulator of VEGF, IL-6 and PEDF in the RPE under hyperglycemic conditions and the p38 mitogen-activated protein kinase pathway mediated this regulatory mechanism.

Effect of a Single Intravitreal Bevacizumab Injection on Proteinuria in Patients With Diabetes.

Purpose: Proteinuria is the second most common complication after hypertension after systemic administration of bevacizumab. Therefore we aimed to analyze the effect of intravitreal bevacizumab (IVB) injection on proteinuria in patients with diabetes. Methods: Patients scheduled to receive IVB injection from May 1, 2018, to December 31, 2018, were prospectively enrolled. In total, 53 patients with diabetes (26 with nonproliferative diabetic retinopathy and 27 with proliferative diabetic retinopathy) and 37 patients without diabetes were included. Urine tests were performed within 1 month of and 7 ± 1 days after IVB injection. Urinary protein, creatinine, and albumin concentrations were quantitatively measured, and urinary protein-to-creatinine ratio and urinary albumin-to-creatinine ratio (UACR) were calculated from these data before and after IVB injection. Results: The mean urinary microalbumin concentrations and urinary protein-to-creatinine ratio were significantly higher in patients with diabetes, both before and after IVB injection. There were no differences between patients with nonproliferative diabetic retinopathy and proliferative diabetic retinopathy. About 80% of patients with diabetes showed improved albuminuria or at least no harmful effect in terms of albuminuria. Patients with deteriorated baseline UACR showed more residual increase in UACR after IVB injection (P < 0.05 in all groups). Conclusions: Close monitoring of renal function after IVB might be needed in patients with diabetes according to the severity of nephropathy. Translational Relevance: Our results may provide information regarding the renal function of IVB-treated patients with diabetes.

Hyperreflective foci in diabetic macular edema with serous retinal detachment: association with dyslipidemia.

AIMS: Hyperreflective foci (HF), detected in the retina of diabetic patients, suggest the presence of microglial activation and migration, while controversies still remain for the origin of HF to be precursors of hard exudates. We investigated the presence of HF and their association with dyslipidemia in serous retinal detachment (SRD)-type diabetic macular edema (DME). METHODS: Forty-two eyes in 42 patients with diabetic retinopathy (DR) and 22 eyes in 22 patients with branch retinal vascular occlusion (BRVO) showing macular edema were included in this study. The medical records and OCT findings were retrospectively reviewed in patients with SRD-type DME and compared with those with BRVO. The mean number of HF, the mean choroidal thickness, and lipid profiles were analyzed and compared between groups. RESULTS: The mean number of HF was significantly higher in DR group compared to BRVO group. Significant correlation of HF was noted with triglycerides (r = 0.523, P = 0.002). Triglycerides were significantly associated with HF by linear regression (ß = 0.012, 95% CI 0.001-0.024, P = 0.034) and remained significantly associated by multiple linear regression (ß = 0.014, 95% CI 0.003-0.025, P = 0.014). CONCLUSIONS: HF on OCT of DME patients could be indicative of activated microglia. HF are associated with dyslipidemia, especially high triglycerides, suggesting inflammatory reaction from dyslipidemia in diabetic retina.

Cell cycle synchronisation using thiazolidinediones affects cellular glucose metabolism and enhances the therapeutic effect of 2-deoxyglucose in colon cancer.

The effect of cell cycle synchronisation on glucose metabolism in cancer cells is not known. We assessed how cell cycle synchronisation by thiazolidinediones (TZDs) can affect glucose uptake by cancer cells and investigated the anti-cancer effect of combination therapy with TZDs and 2-deoxy-glucose (2-DG) in colon cancer cells and in mouse xenograft models. Troglitazone (58.1 ± 2.0 vs 48.6 ± 1.3%, p = 0.002) or pioglitazone (82.9 ± 1.9 vs 61.6 ± 3.4%, p < 0.001) induced cell cycle arrest in SW480 cells at G1 phase. Western blot analysis showed the degradation of cyclin D1 and CDK4, and an increase in the expression levels of p21 and p27 after TZDs treatment. Withdrawal of troglitazone treatment induced significant increase in cellular 3H-DG uptake (141.5% ± 12.9% of controls) and membrane GLUT1 expression levels (146.3% of controls) by 24 h; 1 mM 2-DG treatment alone decreased cell survival by 5.8% as compared with the controls.; however, combination therapy enhanced the anti-tumour effects to 34.6% or 20.3% as compared with control cells. In vivo, each combination treatment group showed significant anti-tumour effects unlike the 2-DG alone group. Cell cycle synchronisation using TZDs induced cellular glucose uptake, which significantly enhanced the therapeutic effect of 2-DG in colon cancer.

PTPRD-inactivation-induced CXCL8 promotes angiogenesis and metastasis in gastric cancer and is inhibited by metformin.

BACKGROUND: Protein tyrosine phosphatase receptor delta (PTPRD) is frequently inactivated in various types of cancers. Here, we explored the underlying mechanism of PTPRD-loss-induced cancer metastasis and investigated an efficient treatment option for PTPRD-inactivated gastric cancers (GCs). METHODS: PTPRD expression was evaluated by immunohistochemistry. Microarray analysis was used to identify differentially expressed genes in PTPRD-inactivated cancer cells. Quantitative reverse transcription (qRT-PCR), western blotting, and/or enzyme-linked immunosorbent assays were used to investigate the PTPRD-CXCL8 axis and the expression of other related genes. An in vitro tube formation assay was performed using HUVECs. The efficacy of metformin was assessed by MTS assay. RESULTS: PTPRD was frequently downregulated in GCs and the loss of PTPRD expression was associated with advanced stage, worse overall survival, and a higher risk of distant metastasis. Microarray analysis revealed a significant increase in CXCL8 expression upon loss of PTPRD. This was validated in various GC cell lines using transient and stable PTPRD knockdown. PTPRD-loss-induced angiogenesis was mediated by CXCL8, and the increase in CXCL8 expression was mediated by both ERK and STAT3 signaling. Thus, specific inhibitors targeting ERK or STAT3 abrogated the corresponding signaling nodes and inhibited PTPRD-loss-induced angiogenesis. Additionally, metformin was found to efficiently inhibit PTPRD-loss-induced angiogenesis, decrease cell viability in PTPRD-inactivated cancers, and reverse the decrease in PTPRD expression. CONCLUSIONS: Thus, the PTPRD-CXCL8 axis may serve as a potential therapeutic target, particularly for the suppression of metastasis in PTPRD-inactivated GCs. Hence, we propose that the therapeutic efficacy of metformin in PTPRD-inactivated cancers should be further investigated.

Insights into the pathogenesis of cystoid macular edema: leukostasis and related cytokines.

Cystoid macular edema (CME) is the abnormal collection of intraretinal fluid in the macular region, especially in the inner nuclear and outer plexiform layers. CME leads to severe visual impairment in patients with various retinal diseases, such as diabetic retinopathy, retinal vascular occlusion, choroidal neovascularization, and uveitis. Although various retinal conditions lead to CME, a shared pathogenesis of CME is involved in these diseases. Accordingly, the pathogenesis of CME based on vasogenic mechanisms is first discussed in this review, including vascular hyperpermeability, leukostasis, and inflammation. We then describe cytotoxic mechanisms based on retinal Müller cell dysfunction. This comprehensive review will provide an understanding of the pathogenesis of CME for potential therapeutic strategies.

Histone deacetylase 6 inhibitor tubastatin A attenuates angiotensin II-induced hypertension by preventing cystathionine γ-lyase protein degradation.

Cystathionine γ-lyase (CSEγ) is a hydrogen sulfide (H2S)-producing enzyme. Endothelial H2S production can mediate vasodilatory effects, contributing to the alleviation of hypertension (high blood pressure). Recent studies have suggested a role of histone deacetylase 6 (HDAC6) in hypertension, although its underlying mechanisms are poorly understood. Here, we addressed the potential regulation of CSEγ by HDAC6 in angiotensin II (AngII)-induced hypertension and its molecular details focusing on CSEγ posttranslational modification. Treatment of mice with a selective HDAC6 inhibitor tubastatin A (TubA) alleviated high blood pressure and vasoconstriction induced by AngII. Cotreatment of the aorta and human aortic endothelial cells with TubA recovered AngII-mediated decreased H2S levels. AngII treatment upregulated HDAC6 mRNA and protein expression, but conversely downregulated CSEγ protein. Notably, potent HDAC6 inhibitors and HDAC6 siRNA as well as a proteasomal inhibitor increased CSEγ protein levels and blocked the downregulatory effect of AngII on CSEγ. In contrast, other HDAC isoforms-specific inhibitors and siRNAs did not show such blocking effects. Transfected CSEγ protein levels were also reciprocally regulated by AngII and TubA, and were reduced by wild-type, but not by deacetylase-deficient, HDAC6. Moreover, TubA significantly increased both protein stability and K73 acetylation level of CSEγ. Consistent with these results, AngII induced CSEγ ubiquitination and degradation, which was inhibited by TubA. Our results indicate that AngII promoted HDAC6-dependent deacetylation of CSEγ at K73 residue, leading to its ubiquitin-mediated proteolysis, which underlies AngII-induced hypertension. Overall, this study suggests that upregulation of CSEγ and H2S through HDAC6 inhibition may be considered as a valid strategy for preventing the progression of hypertension.

Role of Inflammation in Classification of Diabetic Macular Edema by Optical Coherence Tomography.

Diabetic macular edema (DME) is the abnormal accumulation of fluid in the subretinal or intraretinal spaces in the macula in patients with diabetic retinopathy and leads to severely impaired central vision. Technical developments in retinal imaging systems have led to many advances in the study of DME. In particular, optical coherence tomography (OCT) can provide longitudinal and microstructural analysis of the macula. A comprehensive review was provided regarding the role of inflammation using OCT-based classification of DME and current and ongoing therapeutic approaches. In this review, we first describe the pathogenesis of DME, then discuss the classification of DME based on OCT findings and the association of different types of DME with inflammation, and finally describe current and ongoing therapeutic approaches using OCT-based classification of DME. Inflammation has an important role in the pathogenesis of DME, but its role appears to differ among the DME phenotypes, as determined by OCT. It is important to determine how the different DME subtypes respond to intravitreal injections of steroids, antivascular endothelial growth factor agents, and other drugs to improve prognosis and responsiveness to treatment.

MicroRNA-132 Negatively Regulates Palmitate-Induced NLRP3 Inflammasome Activation through FOXO3 Down-Regulation in THP-1 Cells.

Saturated fatty acids were proposed to activate the NLRP3 inflammasome, a molecular platform that mediates the processing of interleukin (IL)-1ß and IL-18. However, the mechanisms underlying the miRNA-mediated regulation of palmitate (PA)-induced inflammasome activation are unclear. We examined the role of miR-132 in PA-induced NLRP3 inflammasome activation in THP-1 cells. To understand the regulatory role of miR-132 in inflammasome activation, we either overexpressed or suppressed miR-132 in THP-1 cells that expressed the NLRP3 inflammasome in response to stimulation by PA. We analyzed the mRNA and protein levels of NLRP3, caspase-1 p10, IL-18, and IL-1ß; caspase-1 activity; and IL-1ß secretion. The presence of PA activated the NLRP3 inflammasome and increased miR-132 expression. Overexpression of miR-132 reduced caspase-1 p10, IL-18, and IL-1ß, while the suppression of miR-132 enhanced inflammasome activation. In addition, miR-132 regulated the mRNA and protein expression of FOXO3, which is a potential target of miR-132 in these cells. FOXO3 suppression by small interfering RNA decreased NLRP3 inflammasome activity stimulated by PA. Knockdown of FOXO3 attenuated NLRP3 inflammasome activation by the miR-132 inhibitor. Based on these findings, we conclude that miR-132 negatively regulates PA-induced NLRP3 inflammasome activation through FOXO3 down-regulation in THP-1 cells.

Involvement of ATF3 in the negative regulation of iNOS expression and NO production in activated macrophages.

Macrophage-associated nitric oxide (NO) production plays a crucial role in the pathogenesis of tissue damage. However, negative factors that regulate NO production remains poorly understood despite its significance of NO homeostasis. Here, we show that activating transcription factor 3 (ATF3), a transcriptional regulator of cellular stress responses, was strongly induced in activated macrophages and its depletion resulted in pronounced enhancement of inducible nitric oxide synthase (iNOS) gene expression and subsequently the induction of high levels of NO production. In response to lipopolysaccharide (LPS) and IFN-γ, ATF3 inhibited transcriptional activity of NF-κB by interacting with the N-terminal (1-200 amino acids) of p65 and was bound to the NF-κB promoter, leading to suppression of iNOS gene expression. In addition, inhibitory effects of ATF3 on iNOS and NO secretion were suppressed by inhibitor of casein kinase II (CK2) activity or its knockdown. Moreover, the levels of ATF3 were highly elevated in established cecal ligation and puncture or LPS-injected mice, a model of endotoxemia. ATF3 is also elevated in peritoneal macrophages. Collectively, our findings suggest that ATF3 regulates NO homeostasis by associating with NF-κB component, leading to the repression of its transcriptional activity upon inflammatory signals and points to its potential relevance for the control of cell injuries mediated by NO during macrophage activation.

Chinese yam extracts containing ß-sitosterol and ethyl linoleate protect against atherosclerosis in apolipoprotein E-deficient mice and inhibit muscular expression of VCAM-1 in vitro.

Atherosclerosis is a chronic inflammatory disease, which is associated with increased expression of adhesion molecules and monocyte recruitment into the arterial wall. This study evaluated whether hexane extracts from the edible part (DB-H1) or bark region (DB-H2) of Dioscorea. batatas Decne have anti-atherosclerotic properties in vivo and in vitro experiments. We also identified bioactive components in the hexane extracts. Thirty-six apolipoprotein E (ApoE(-/-) ) mice and 12 control (C57BL/6J) mice were given a Western-type diet for 11 or 21 wk. To examine the effects of yam extracts on lesion development, ApoE(-/-) mice were orally administered DB-H1 or DB-H2 for the duration of the study (200 mg/kg b.w./day, 3 times per wk). Both DB-H1 and DB-H2 significantly reduced the total atherosclerotic lesion area in the aortic root. In addition, plasma concentrations of total cholesterol, oxidized-low-density lipoprotein, and c-reactive protein were decreased by administration of DB-H1 and DB-H2. Consistent with the in vivo observations, DB-H1 and DB-H2 inhibited tumor necrosis factor (TNF)-α-induced vascular cell adhesion molecule-1 expression and adhesion of THP-1 monocytes to TNF-α-activated vascular smooth muscle cells. It was also found that treatment with DB-H1 or DB-H2 resulted in the inhibition nitric oxide (NO) and reactive oxygen species production and iNOS expression in macrophages. Thus, DB-H1 and DB-H2 seem to influence atherosclerosis by affecting the production of inflammatory mediators in vivo. Our results suggest that yam extracts have the potential to be used in the prevention of atherosclerosis.

Ohioensin F suppresses TNF-α-induced adhesion molecule expression by inactivation of the MAPK, Akt and NF-κB pathways in vascular smooth muscle cells.

AIMS: The expression of cell adhesion molecules on vascular smooth muscle cells is central to leukocyte recruitment and progression of atherosclerotic disease. Ohioensin F, a chemical compound of the Antarctic moss Polyerichastrum alpinum, exhibited inhibitory activity against protein tyrosine phosphatase 1B and antioxidant activity. However, published scientific information regarding other biological activities and pharmacological function of ohioensin F is scarce. In the present study, we aimed to examine the in vitro effects of ohioensin F on the ability to suppress TNF-α-induced adhesion molecule expression in vascular smooth muscle cells (VSMCs). MAIN METHODS: The inhibitory effect of ohioensin F on TNF-α-induced upregulation in expression of adhesion molecules was investigated by enzyme-linked immunosorbent assay, cell adhesion assay, RT-PCR, western blot analysis, immunofluorescence, and transfection and reporter assay, respectively. KEY FINDINGS: Pretreatment of VSMCs with ohioensin F at nontoxic concentrations of 0.1-10 µg/ml dose-dependently inhibited TNF-α-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). In addition, ohioensin F suppressed adhesion of THP-1 monocytes to TNF-α-stimulated VSMCs. Ohioensin F reduced TNF-α-induced production of intracellular reactive oxygen species (ROS) and phosphorylation of p38, ERK, JNK and Akt. Finally, ohioensin F inhibited TNF-α-induced CAM mRNA expression and NK-κB translocation. SIGNIFICANCE: These results suggest a new mechanism of ohioensin F's anti-inflammatory action, owing to the negative regulation of TNF-α-induced adhesion molecule expression, monocyte adhesion and ROS production in vascular smooth muscle cells. Our finding also supports ohioensin F as a potential pharmacological, anti-inflammatory molecule that has a protective effect on the atherosclerotic lesion.

Stereocalpin A inhibits the expression of adhesion molecules in activated vascular smooth muscle cells.

Up-regulation of cell adhesion molecules on vascular smooth muscle cells (VSMCs) and leukocyte recruitment to the vascular wall contribute to vascular inflammation and atherosclerosis. Stereocalpin A, a chemical compound of the Antarctic lichen Ramalina terebarata, displays tumoricidal activity against several different tumor cell types. However, other biological activities of stereocalpin A and its molecular mechanisms remain unknown. In this study, our work is directed toward studying the in vitro effects of stereocalpin A on the ability to suppress the expression of adhesion molecules induced by TNF-α in vascular smooth muscle cells. Pretreatment of VSMCs for 2h with stereocalpin A at nontoxic concentrations of 0.1-10 µg/ml inhibited TNF-α-induced adhesion of THP-1 monocytic cells and expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). Stereocalpin A reduced TNF-α-induced production of intracellular reactive oxygen species (ROS) and phosphorylation of p38, ERK, JNK and Akt. Stereocalpin A also inhibited NK-κB activation induced by TNF-α. Moreover, stereocalpin A inhibited TNF-α-induced ΙκΒ kinase activation, subsequent degradation of ΙκΒα, and nuclear translocation of NF-κB. Hence, we describe a new anti-inflammatory activity and mechanism of stereocalpin A, owing to the negative regulation of TNF-α-induced adhesion molecule and MCP-1 expression, monocyte adhesion and ROS production in vascular smooth muscle cells. These results suggest that stereocalpin A has the potential to exert a protective effect by modulating inflammation within the atherosclerotic lesion.