Ramalin inhibits VCAM-1 expression and adhesion of monocyte to vascular smooth muscle cells through MAPK and PADI4-dependent NF-kB and AP-1 pathways

Investigating the cell membrane localization of PADI4 in breast cancer cells and inhibition of anti-PADI4 monoclonal antibody

BACKGROUND

Peptidyl arginine deiminase 4 (PADI4) is a post-translational modification enzymecan that converts arginine in protein into citrulline in the presence of calcium ions, which is called citrullination. PADI4 has been reported to be expressed in the cytoplasm and nucleus in a variety of malignant tumors. Based on the GeneCards database and our previous research, it is speculated that PADI4 may also be expressed on the cell membrane. This study aimed to confirm the membrane expression of PADI4 and the effect of anti-PADI4 antibodies on cell membrane PADI4. This may be another mechanism of action of anti-PADI4 monoclonal antibodies in the treatment of breast cancer.

METHODS

The subcellular localizations of PADI4 in MDA-MB-231 and MCF-7 breast cancer cells were determined by immunofluorescence, immunoelectron microscopy, and Western blot analysis. The tumor cells were treated with PADI4 antibody, and cell proliferation, migration, colony formation, apoptosis, glycolysis, and epithelial-mesenchymal transition (EMT) were measured as well as the expression of some essential tumor genes.

RESULTS

PADI4 was not only localized in the nucleus and cytoplasm of breast cancer cells but was also detected on the cell membrane. Following PADI4 antibody treatment, cell proliferation, migration, colony formation, EMT, and ATP production through glycolysis were decreased, and the mRNA expression of MYC proto-oncogene (MYC), FAT atypical cadherin 1 (FAT1), nuclear factor kappa B subunit 1 (NFκB), and tumor necrosis factor (TNF-α) in breast cancer cells was downregulated, while the mRNA expression of tumor protein p63 (TP63) was upregulated.

CONCLUSIONS

PADI4 is expressed on the cell membrane in breast cancer cells. Anti-PADI4 antibodies can affect the biological functions of cell membrane PADI4, including proliferation, migration, apoptosis, and glycolysis, thereby inhibiting tumor progression.

Role of the PADI family in inflammatory autoimmune diseases and cancers: A systematic review

The peptidyl arginine deiminase (PADI) family is a calcium ion-dependent group of isozymes with sequence similarity that catalyze the citrullination of proteins. Histones can serve as the target substrate of PADI family isozymes, and therefore, the PADI family is involved in NETosis and the secretion of inflammatory cytokines. Thus, the PADI family is associated with the development of inflammatory autoimmune diseases and cancer, reproductive development, and other related diseases. In this review, we systematically discuss the role of the PADI family in the pathogenesis of various diseases based on studies from the past decade to provide a reference for future research.

Clinical significance of neutrophil extracellular traps biomarkers in thrombosis

Neutrophil extracellular traps (NETs) may be associated with the development of thrombosis. Experimental studies have confirmed the presence of NETs in thrombi specimens and potential role of NETs in the mechanisms of thrombosis. Clinical studies also have demonstrated significant changes in the levels of serum or plasma NETs biomarkers, such as citrullinated histones, myeloperoxidase, neutrophil elastase, nucleosomes, DNA, and their complexes in patients with thrombosis. This paper aims to comprehensively review the currently available evidence regarding the change in the levels of NETs biomarkers in patients with thrombosis, summarize the role of NETs and its biomarkers in the development and prognostic assessment of venous thromboembolism, coronary artery diseases, ischemic stroke, cancer-associated thromboembolism, and coronavirus disease 2019-associated thromboembolism, explore the potential therapeutic implications of NETs, and further discuss the shortcomings of existing NETs biomarkers in serum and plasma and their detection methods.

Neutrophil extracellular traps modulate inflammatory markers and uptake of oxidized LDL by human and murine macrophages

Neutrophil extracellular traps (NETs) are web-like structures, which are released upon neutrophil activation. It has previously been demonstrated that NETs are present in atherosclerotic lesions of both humans and animal models thus playing a decisive role in atherosclerosis. Besides, macrophages have a crucial role in disease progression, whereby classically activated M1 macrophages sustain inflammation and alternatively activated M2 macrophages display anti-inflammatory effects. Although NETs and macrophages were found to colocalize in atherosclerotic lesions, the impact of NETs on macrophage function is not fully understood. In the present study, we aimed to investigate the effect of NETs on human and murine macrophages in respect to the expression of pro-inflammatory cytokines, matrix metalloproteinases (MMPs) and uptake of oxidized LDL (oxLDL) in vitro. Human THP-1 and murine bone marrow-derived macrophages were cultured under M1 (LPS + IFN-γ)- and M2a (IL-4)-polarizing culture conditions and treated with NETs. To mimic intraplaque regions, cells were additionally cultured under hypoxic conditions. NETs significantly increased the expression of IL-1β, TNF-α and IL-6 in THP-M1 macrophages under normoxia but suppressed their expression in murine M1 macrophages under hypoxic conditions. Notably, NETs increased the number of oxLDL-positive M1 and M2 human and murine macrophages under normoxia, but did not influence formation of murine foam cells under hypoxia. However, oxLDL uptake did not strongly correlate with the expression of the LDL receptor CD36. Besides, upregulated MMP-9 expression and secretion by macrophages was detected in the presence of NETs. Again, hypoxic culture conditions dampened NETs effects. These results suggest that NETs may favor foam cell formation and plaque vulnerability, but exert opposite effects in respect to the inflammatory response of human and murine M1 macrophages. Moreover, effects of NETs on macrophages’ phenotype are altered under hypoxia.

Potential of Ramalin and Its Derivatives for the Treatment of Alzheimer's Disease

The pathogenesis of Alzheimer's disease (AD) is still unclear, and presently there is no cure for the disease that can be used for its treatment or to stop its progression. Here, we investigated the therapeutic potential of ramalin (isolated from the Antarctic lichen, Ramalina terebrata), which exhibits various physiological activities, in AD. Specifically, derivatives were synthesized based on the structure of ramalin, which has a strong antioxidant effect, BACE-1 inhibition activity, and anti-inflammatory effects. Therefore, ramalin and its derivatives exhibit activity against multiple targets associated with AD and can serve as potential therapeutic agents for the disease.

Urantide attenuates myocardial damage in atherosclerotic rats by regulating the MAPK signalling pathway

OBJECTIVE

To explore the effect of urantide on atherosclerotic myocardial injury by antagonizing the urotensin II/urotensin II receptor (UII/UT) system and regulating the mitogen-activated protein kinase (MAPK) signalling pathway.

METHODS

Atherosclerosis (AS) was established in rats by administering a high-fat diet and an intraperitoneal injection of vitamin D₃. The effect of treatment with urantide (30 μg/kg), a UII receptor antagonist, for 3, 7, or 14 days on AS-induced myocardial damage was evaluated.

RESULTS

The heart of rats with AS exhibited pathological changes suggestive of myocardial injury, and the serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH) were significantly increased. Additionally, significant increases in the levels of UII, its receptor (G protein-coupled receptor 14, GPR14), p-P38, p-extracellular signal-regulated kinase (ERK) and p-c-Jun N-terminal kinase (JNK) were observed in the heart. Urantide improved pathological changes in the heart of rats with AS and reduced the serum CK and LDH levels. Additionally, the UII antagonist decreased the increased levels of UII, GPR14, p-P38, p-ERK and p-JNK in the heart.

CONCLUSIONS

Urantide alleviates atherosclerotic myocardial injury by inhibiting the UII-GPR14 interaction and regulating the MAPK signalling pathway. We hypothesized that myocardial injury may be associated with the regulation of the MAPK signalling pathway.

Mechanical stretching of pulmonary vein stimulates matrix metalloproteinase-9 and transforming growth factor-β1 through stretch-activated channel/MAPK pathways in pulmonary hypertension due to left heart disease model rats

Pulmonary hypertension due to left heart disease (PH-LHD) is a momentous pulmonary hypertension disease, and left heart disease is the most familiar cause. Mechanical stretching may be a crucial cause of vascular remodeling. While, the underlining mechanism of mechanical stretching-induced in remodeling of pulmonary vein in the early stage of PH-LHD has not been completely elucidated. In our study, the PH-LHD model rats were successfully constructed. After 25 days, doppler echocardiography and hemodynamic examination were performed. In addition, after treatment, the levels of matrix metalloproteinase-9 (MMP-9) and transforming growth factor-β1 (TGF-β1) were determined by ELISA, immunohistochemistry and western blot assays in the pulmonary veins. Moreover, the pathological change of pulmonary tissues was evaluated by H&E staining. Our results uncovered that left ventricular insufficiency and interventricular septal shift could be observed in PH-LHD model rats, and the right ventricular systolic pressure (RVSP) and mean left atrial pressure (mLAP) were also elevated in PH-LHD model rats. Meanwhile, we found that MMP-9 and TGF-β1 could be highly expressed in PH-LHD model rats. Besides, we revealed that stretch-activated channel (SAC)/mitogen-activated protein kinases (MAPKs) signaling pathway could be involved in the upregulations of MMP-9 and TGF-β1 mediated by mechanical stretching in pulmonary vein. Therefore, current research revealed that mechanical stretching induced the increasing expressions of MMP-9 and TGF-β1 in pulmonary vein, which could be mediated by activation of SAC/MAPKs signaling pathway in the early stage of PH-LHD.

Neutrophil Extracellular Traps Participate in Cardiovascular Diseases: Recent Experimental and Clinical Insights

Neutrophil extracellular traps (NETs) have recently emerged as a newly recognized contributor to venous and arterial thrombosis. These strands of DNA extruded by activated or dying neutrophils, decorated with various protein mediators, become solid-state reactors that can localize at the critical interface of blood with the intimal surface of diseased arteries and propagate and amplify the regional injury. NETs thus furnish a previously unsuspected link between inflammation, innate immunity, thrombosis, oxidative stress, and cardiovascular diseases. In response to disease-relevant stimuli, neutrophils undergo a specialized series of reactions that culminate in NET formation. DNA derived from either nuclei or mitochondria can contribute to NET formation. The DNA liberated from neutrophils forms a reticular mesh that resembles morphologically a net, rendering the acronym NETs particularly appropriate. The DNA backbone of NETs not only presents intrinsic neutrophil proteins (eg, MPO [myeloperoxidase] and various proteinases) but can gather other proteins found in blood (eg, tissue factor procoagulant). This review presents current concepts of neutrophil biology, the triggers to and mechanisms of NET formation, and the contribution of NETs to atherosclerosis and to thrombosis. We consider the use of markers of NETs in clinical studies. We aim here to integrate critically the experimental literature with the growing body of clinical information regarding NETs.

Nutraceuticals for prevention of atherosclerosis: Targeting monocyte infiltration to the vascular endothelium

Cardiovascular disease (CVD) is the leading cause of death, globally, and is a serious problem in developing countries. Preventing atherosclerosis is key to reducing the risk of developing CVD. Similar to carcinogenesis, atherogenesis can be divided into four stages: initiation, promotion, progression, and acute events. The current study focuses on the promotion stage, which is characterized by circular monocyte penetration into vascular endothelial cells, monocyte differentiation into macrophages, and the formation of foam cells. This early stage of atherogenesis is a major target for nutraceuticals. We discuss nutraceuticals that can potentially inhibit monocyte adhesion to the vascular endothelium, thereby preventing the promotional stage of atherosclerosis. The mechanisms through which these nutraceuticals prevent monocyte adhesion are classified according to the following targets: NF-κB, ROS, MAPKs, and AP-1. Additionally, we discuss promising targets for nutraceuticals that can regulate monocyte adhesion to the endothelium. PRACTICAL APPLICATIONS: Introduction of atherogenesis with initiation, promotion, progression, and acute events provide specific information and factors for each step in the development of atherosclerosis. Functional food or pharmaceutical researchers can set target stages and use them to develop materials that control atherosclerosis. In particular, because it focuses on vascular inflammation via interaction between monocytes and vascular endothelial cells, it provides specific information to researchers developing functional foods that regulate this process. Therefore, this manuscript, unlike previous papers, will provide material information and potential mechanisms of action to researchers who want to develop functional foods that control vascular inflammation rather than vascular lipids.

Dexmedetomidine Attenuates Monocyte-Endothelial Adherence via Inhibiting Connexin43 on Vascular Endothelial Cells

Current studies have identified the multifaceted protective functions of dexmedetomidine on multiple organs. For the first time, we clarify effects of dexmedetomidine on monocyte-endothelial adherence and whether its underlying mechanism is relative to connexin43 (Cx43), a key factor regulating monocyte-endothelial adherence. U937 monocytes and human umbilical vein endothelial cells (HUVECs) were used to explore monocyte-endothelial adherence. Two special siRNAs were designed to knock down Cx43 expression on HUVECs. U937-HUVEC adhesion, adhesion-related molecules, and the activation of the MAPK (p-ERK1/2, p-p38, and p-JNK1/2) signaling pathway were detected. Dexmedetomidine, at its clinically relevant concentrations (0.1 nM and 1 nM), was given as pretreatments to HUVECs. Its effects on Cx43 and U937-HUVEC adhesion were also investigated. The results show that inhibiting Cx43 on HUVECs could attenuate the contents of MCP-1, soluble ICAM-1 (sICAM-1), soluble VCAM-1 (sVCAM-1), and the nonprocessed variants of the adhesion molecules ICAM-1 and VCAM-1 and ultimately result in U937-HUVEC adhesion decrease. Meanwhile, the activation of MAPKs was also inhibited. U0126 (inhibiting p-ERK1/2) and SB202190 (inhibiting p38) decreased the contents of MCP-1, sICAM-1, and sVCAM-1, but SP600125 (inhibiting p-JNK1/2) had none of these effects. ICAM-1 and VCAM-1 could be regulated in a similar way. Dexmedetomidine pretreatment inhibited Cx43 on HUVECs, the activation of MAPKs, and U937-HUVEC adhesion. Therefore, we conclude that dexmedetomidine attenuates U937-HUVEC adhesion via inhibiting Cx43 on HUVECs modulating the activation of MAPK signaling pathways.

Anti-inflammatory and antioxidative effects of Dan-Lou tablets in the treatment of coronary heart disease revealed by metabolomics integrated with molecular mechanism studies

ETHNOPHARMACOLOGICAL EVIDENCE

The Dan-Lou tablet (DLT), a well-known Chinese prescription, has definitive clinical efficacy in the treatment of precordial discomfort and pain caused by coronary heart disease (CHD). However, the pharmacological mechanism of DLT in the treatment of CHD has not been clearly elucidated and needs to be further explored.

AIM OF THE STUDY

We aimed to identify relevant biological pathways by assessing changes in biomarkers in response to DLT intervention in CHD to reveal the potential biological mechanism of DLT treatment for CHD.

MATERIALS AND METHODS

The major chemical components in DLT were qualitatively analyzed using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS), and a model of CHD in rats was subsequently established with a high-fat diet and left anterior coronary artery ligation (LADCA) followed by DLT intervention. Next, the metabolic profile of rat serum samples was analyzed using nontargeted metabolomics, wherein changes in the metabolites in serum samples before and after DLT administration were measured by PLS-DA, and two pathways of DLT treatment for CHD were predicted. Finally, predicted metabolomic pathways were verified by detecting and analyzing tissues from the rat model, revealing the mechanism of DLT in the treatment of CHD.

RESULTS

Forty-five major chemical components were identified by the chemical characterization of DLT. In terms of metabolism, 17 biomarkers of CHD in rats were identified. Among these biomarkers, linoleic acid, γ-linolenic acid and lysophosphatidylcholines (LPCs) were found to play an important role in energy metabolism and glycerophospholipid metabolism. Protein analysis revealed that EGFR phosphorylation was inhibited in CHD rats after DLT treatment, which lowered the expression of TNF-α, IL-6 and MMP9, decreased the expression levels of ox-LDL and MDA, and increased the expression of SOD.

CONCLUSION

The mechanism of DLT in the treatment of CHD involves inhibiting the expression of EGFR and the activation of the MAPK signaling pathway by regulating glycerophospholipid metabolism (LPCs) and energy metabolism (linoleic acid and γ-linolenic acid). Therefore, inflammation-related (TNF-α, IL-6, MMP9) and oxidative stress-related (ox-LDL, MDA, SOD) indicators are affected, leading to the regulation of the oxidative stress state and anti-inflammatory effects.

Treponema pallidum Induces the Secretion of HDVSMC Inflammatory Cytokines to Promote the Migration and Adhesion of THP-1 Cells

The pathological features of syphilis, a disease caused by Treponema pallidum (T. pallidum), are characterized by vascular involvement with endarteritis and periarteritis. Little is known about the interactions of infiltrating immunocytes with human dermal vascular smooth muscle cells (HDVSMCs) in arterioles during the immunopathogenesis of syphilis. In the present study, we demonstrated that stimulation of HDVSMCs with T. pallidum resulted in the upregulated gene transcription and protein expression of interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1), and intercellular adhesion molecule-1 (ICAM-1) in a dose- and time-dependent manner. Moreover, the migration and adhesion of THP-1 cells to HDVSMCs were significantly suppressed by anti-MCP-1 and anti-ICAM-1 neutralizing antibodies, respectively. Further studies revealed that T. pallidum activated the NF-κB signaling pathway in HDVSMCs. Inhibition of NF-κB suppressed T. pallidum-induced IL-6, MCP-1, and ICAM-1 expression. In addition, the migration and adhesion of THP-1 cells to T. pallidum-treated HDVSMCs were significantly decreased by pretreatment with an NF-κB inhibitor. These findings demonstrate that T. pallidum induces the production of IL-6, MCP-1, and ICAM-1 in HDVSMCs and promotes the adherence and migration of THP-1 cells to HDVSMCs through the NF-κB signaling pathway, which may provide new insight into the pathogenesis of T. pallidum infection.

Melatonin Inhibits in Vitro Smooth Muscle Cell Inflammation and Proliferation and Atherosclerosis in Apolipoprotein E-Deficient Mice

Chronic inflammation and proliferation play important roles in atherosclerosis progression. This study aimed to identify the mechanisms responsible for the anti-inflammatory and antiproliferative effects of melatonin on tumor necrosis factor-α (TNF-α)- and platelet-derived growth factor-BB (PDGF-BB)-treated rat aortic smooth muscle cells (RASMCs). Melatonin reduced TNF-α-induced RASMC inflammation by decreasing vascular cell adhesion molecule-1 (VCAM-1) expression and nuclear factor-kappa B (NF-κB) P65 activity by inhibiting P38 mitogen-activated protein kinase phosphorylation ( P < 0.05). Additionally, melatonin inhibited PDGF-BB-induced RASMC proliferation by reducing mammalian target of rapamycin (mTOR) phosphorylation ( P < 0.05) but not migration in vitro. Melatonin also reduced TNF-α- and PDGF-BB-induced reactive oxygen species (ROS) production ( P < 0.05). Furthermore, melatonin treatment (prevention and treatment groups) significantly repressed high cholesterol diet-stimulated atherosclerotic lesions in vivo (19.59 ± 4.11%, 20.28 ± 5.63%, 32.26 ± 12.06%, respectively, P < 0.05). Taken together, the present study demonstrated that melatonin attenuated TNF-α-induced RASMC inflammation and PDGF-BB-induced RASMC proliferation in cells and reduced atherosclerotic lesions in mice. These results showed that melatonin has anti-inflammatory and antiproliferative properties and may be a novel therapeutic target in atherosclerosis.

Recent Advances in Understanding the Pathogenesis of Cardiovascular Diseases and Development of Treatment Modalities

Cardiovascular Diseases (CVDs) are a leading cause of morbidity and mortality worldwide. The underlying pathology for cardiovascular disease is largely atherosclerotic in nature and the steps include fatty streak formation, plaque progression and plaque rupture. While there is optimal drug therapy available for patients with CVD, there are also underlying drug delivery obstacles that must be addressed. Challenges in drug delivery warrant further studies for the development of novel and more efficacious medical therapies. An extensive understanding of the molecular mechanisms of disease in combination with current challenges in drug delivery serves as a platform for the development of novel drug therapeutic targets for CVD. The objective of this article is to review the pathogenesis of atherosclerosis, first-line medical treatment for CVD, and key obstacles in an efficient drug delivery.

RNAi-Based Identification of Gene-Specific Nuclear Cofactor Networks Regulating Interleukin-1 Target Genes

The potent proinflammatory cytokine interleukin (IL)-1 triggers gene expression through the NF-κB signaling pathway. Here, we investigated the cofactor requirements of strongly regulated IL-1 target genes whose expression is impaired in p65 NF-κB-deficient murine embryonic fibroblasts. By two independent small-hairpin (sh)RNA screens, we examined 170 genes annotated to encode nuclear cofactors for their role in Cxcl2 mRNA expression and identified 22 factors that modulated basal or IL-1-inducible Cxcl2 levels. The functions of 16 of these factors were validated for Cxcl2 and further analyzed for their role in regulation of 10 additional IL-1 target genes by RT-qPCR. These data reveal that each inducible gene has its own (quantitative) requirement of cofactors to maintain basal levels and to respond to IL-1. Twelve factors (Epc1, H2afz, Kdm2b, Kdm6a, Mbd3, Mta2, Phf21a, Ruvbl1, Sin3b, Suv420h1, Taf1, and Ube3a) have not been previously implicated in inflammatory cytokine functions. Bioinformatics analysis indicates that they are components of complex nuclear protein networks that regulate chromatin functions and gene transcription. Collectively, these data suggest that downstream from the essential NF-κB signal each cytokine-inducible target gene has further subtle requirements for individual sets of nuclear cofactors that shape its transcriptional activation profile.

Roles of PAD4 and NETosis in Experimental Atherosclerosis and Arterial Injury: Implications for Superficial Erosion

RATIONALE

Neutrophils likely contribute to the thrombotic complications of human atheromata. In particular, neutrophil extracellular traps (NETs) could exacerbate local inflammation and amplify and propagate arterial intimal injury and thrombosis. PAD4 (peptidyl arginine deiminase 4) participates in NET formation, but an understanding of this enzyme's role in atherothrombosis remains scant.

OBJECTIVE

This study tested the hypothesis that PAD4 and NETs influence experimental atherogenesis and in processes implicated in superficial erosion, a form of plaque complication we previously associated with NETs.

METHODS AND RESULTS

Bone marrow chimeric Ldlr deficient mice reconstituted with either wild-type or PAD4-deficient cells underwent studies that assessed atheroma formation or procedures designed to probe mechanisms related to superficial erosion. PAD4 deficiency neither retarded fatty streak formation nor reduced plaque size or inflammation in bone marrow chimeric mice that consumed an atherogenic diet. In contrast, either a PAD4 deficiency in bone marrow-derived cells or administration of DNaseI to disrupt NETs decreased the extent of arterial intimal injury in mice with arterial lesions tailored to recapitulate characteristics of human atheroma complicated by erosion.

CONCLUSIONS

These results indicate that PAD4 from bone marrow-derived cells and NETs do not influence chronic experimental atherogenesis, but participate causally in acute thrombotic complications of intimal lesions that recapitulate features of superficial erosion.

PADI4 has genetic susceptibility to gastric carcinoma and upregulates CXCR2, KRT14 and TNF-α expression levels

PADI4 (peptidyl deiminase isoform 4) is overexpressed in many tumor tissues and converts arginine residues to citrulline residues. This study used an Illumina SNP microarray and a TaqMan assay to determine the possible association of the PADI4 gene with various tumor risks. Both genotyping methods demonstrated significant associations between the tag SNPs rs1635566 and rs882537 in the PADI4 locus with gastric carcinoma in two independent cohorts. Based on this genotyping result, we used the Cancer Pathway Finder, p53 Signaling, Signal Transduction and Tumor Metastasis PCR arrays to investigate the tumorigenic pathway of PADI4 in MNK-45 cells derived from gastric carcinoma. We detected significantly decreased expression levels of CXCR2, KRT14 and TNF-α in MNK-45 cells that were treated with anti-PADI4 siRNA. We also detected increased expression of these three genes in MNK-45 cells transfected with a pcDNA3.1 plasmid overexpressing PADI4. A highly similar result was also obtained for SGC 7901 cells, which also originate from gastric carcinoma. Our result indicates that the PADI4 gene has genetic susceptibility in gastric carcinoma. PADI4 contributes to gastric tumorigenesis by upregulating CXCR2, KRT14 and TNF-α expression, which are well known to activate angiogenesis, cell proliferation, cell migration and the immune microenvironment in tumors.

Design, synthesis and biological evaluation of glutamic acid derivatives as anti-oxidant and anti-inflammatory agents

A series of glutamic acid derivatives was synthesized and evaluated for their antioxidant activity and stability. We found several potent and stable glutamic acid derivatives. Among them, compound 12b exhibited good in vitro activity, chemical stability and cytotoxicity. A prototype compound 12b showed an anti-inflammatory effect in LPS-stimulated RAW 264.7 cell lines and in a zebrafish model.

Raf Kinase Inhibitor Protein (RKIP) Inhibits Tumor Necrosis Factor-α (TNF-α) Induced Adhesion Molecules Expression in Vascular Smooth Muscle Bells by Suppressing (Nuclear Transcription Factor-κB (NF-kappaB) Pathway

Background

Raf kinase inhibitor protein (RKIP) regulates growth and differentiation and plays a role in key signal transduction cascades in mammalian cells. Nevertheless, the underlying mechanism for which RKIP regulates cell-cell adhesion remains unknown. Our study investigated the function of the RKIP overexpression on adhesion molecules expression induced by tumor necrosis factor (TNF)-α in cultured mouse vascular smooth muscle cells (MOVACs).

Material/Methods

The expression levels of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were detected by ELISA kit, reverse transcription-PCR, and western blot assays. The protein expression of RKIP, p65, and inhibitor of nuclear factor (NF)-κBα (IκBα) were detected by western blot analysis. The activity of NF-kappaB was determined using a Dual-Luciferase Reporter assay.

Results

The results showed that MOVACs transfected with pCMV5-HA-RKIP significantly inhibited TNF-α induced mRNA and protein expression of ICAM-1 and VCAM-1. The adhesion of THP-1 cells was also detected and inhibited by pCMV5-HA-RKIP in TNF-α-treated MOVACs. RKIP also suppressed the TNF-α-induced activation of NF-kappaB and the protein expression of phosphorylated IκB-α, and promoted the protein expression of IκB-α and nuclear translocation of p65 NF-kappaB. Furthermore, RKIP and the inhibitor of NF-kappaB (BAY11-7082) reduced the upregulation of ICAM-1 and VACM-1 induced by TNF-α.

Conclusions

Taken together, these results suggested that RKIP may inhibit the TNF-α-induced expression of adhesion molecules in MOVACs through inactivation of the NF-kappaB pathway.

Mechanism of the effect of saikosaponin on atherosclerosis in vitro is based on the MAPK signaling pathway

The present study aimed to investigate the effects of saikosaponin on oxidized low‑density lipoprotein (ox‑LDL)‑induced human umbilical vein endothelial cell (HUVEC) injury and apoptosis, and examine the involvement of the mitogen‑activated protein kinase (MAPK) signaling pathway. The viability and apoptosis of HUVECs were detected using an MTT assay and flow cytometry. ELISA analysis was applied to measure the levels of tumor necrosis factor (TNF)‑α and interleukin (IL)‑6 cytokines. Nuclear factor (NF)‑κB p65 nuclear translocation was observed using immunofluorescence staining. The levels of intercellular adhesion molecule 1 and vascular cell adhesion molecule‑1 were detected using reverse transcription‑polymerase chain reaction analysis. The phosphorylation of B‑cell lymphoma 2 (Bcl‑2), Bcl‑2‑associated X protein (Bax), caspase‑3 p38, c‑Jun N‑terminal kinase (JNK) and extracellular signal‑regulated kinase (ERK)1/2 were detected using western blot analysis. The results revealed that saikosaponin increased the viability of the HUVECs and decreased the early‑stage apoptotic rate of the HUVECs induced by ox‑LDL. The expression levels of inflammatory cytokines in the injured vascular endothelial cells were decreased, the expression levels of adhesion molecules were reduced, the activity of superoxide dismutase was increased, and malondialdehyde content was decreased. Therefore, the inflammatory response and oxidative stress were inhibited. Simultaneously, the levels of Bcl‑2 increased, the levels of Bax and caspase‑3 decreased, and the nuclear translocation of NF‑κB p65 was significantly inhibited. The protein levels of phosphorylated p38 and JNK were reduced, whereas that of ERK1/2 remained unaffected. It was concluded that the MAPK signaling pathway mediated HUVEC injury induced by ox‑LDL. However, saikosaponin inhibited the HUVEC injury induced by ox‑LDL through inhibiting the ERK1/2 and p38 MAPK signaling pathways, and possibly also through the JNK and p38 MAPK signaling pathway.

Ramalin Isolated from Ramalina Terebrata Attenuates Atopic Dermatitis-like Skin Lesions in Balb/c Mice and Cutaneous Immune Responses in Keratinocytes and Mast Cells

Atopic dermatitis (AD) is a chronic inflammatory skin disease that involves eczematous skin lesions with pruritic erythematous papules. In this study, we investigated the mitigating effects of ramalin, a component of the Antarctic lichen Ramalina terebrata against AD in vivo and in vitro. Oral administration of ramalin lessened scratching behaviors and significantly reduced both serum immunoglobulin E and IL-4 levels, and mRNA levels of IL-4 and IL-10 in AD-induced Balb/c mice. In vitro, treatment with ramalin produced significantly less inflammatory chemokines and cytokines, including TARC, MCP-1, RANTES, and IL-8 in TNF-α-stimulated HaCaT cells. In addition, ramalin inhibited the activation of nuclear factor-kappa B as well as the phosphorylation of mitogen-activated protein kinases (MAPK). Furthermore, ramalin treatment resulted in decreased production of β-hexosaminidase and proinflammatory cytokines IL-4, IL-6, and TNF-α in 2,4 dinitrophenyl-human serum albumin-stimulated RBL-2H3 cells through blocking MAPK signaling pathways. The results suggest that ramalin modulates the production of immune mediators by inhibiting the nuclear factor-kappa B and MAPK signaling pathways. Taken together, ramalin effectively attenuated the development of AD and promoted the mitigating effects on Th2 cell-mediated immune responses and the production of inflammatory mediators in mast cells and keratinocytes. Thus, ramalin may be a potential therapeutic agent for AD. Copyright © 2016 John Wiley & Sons, Ltd.