The Role of Human Endogenous Retrovirus (HERV)-K119 env in THP-1 Monocytic Cell Differentiation.

Human endogenous retrovirus (HERV)-K was reportedly inserted into the human genome millions of years ago and is closely related to various diseases, including cancer and immune regulation. In our previous studies, CRISPR-Cas9-enabled knockout (KO) of the HERV-K env gene was found to potentially reduce cell proliferation, cell migration, and invasion in colorectal and ovarian cancer cell lines. The immune response involves the migration and invasion of cells and is similar to cancer; however, in certain ways, it is completely unlike cancer. Therefore, we induced HERV-K119 env gene KO in THP-1, a monocytic cell that can be differentiated into a macrophage, to investigate the role of HERV-K119 env in immune regulation. Cell migration and invasion were noted to be significantly increased in HERV-K119 env KO THP-1 cells than in MOCK, and these results were contrary to those of cancer cells. To identify the underlying mechanism of HERV-K119 env KO in THP-1 cells, transcriptome analysis and cytokine array analysis were conducted. Semaphorin7A (SEMA7A), which induces the production of cytokines in macrophages and monocytic cells and plays an important role in immune effector cell activation during an inflammatory immune response, was significantly increased in HERV-K119 env KO THP-1 cells. We also found that HERV-K119 env KO THP-1 cells expressed various macrophage-specific surface markers, suggesting that KO of HERV-K119 env triggers the differentiation of THP-1 cells from monocytic cells into macrophages. In addition, analysis of the expression of M1 and M2 macrophage markers showed that M1 macrophage marker cluster of differentiation 32 (CD32) was significantly increased in HERV-K119 env KO cells. These results suggest that HERV-K119 env is implicated in the differentiation of monocytic cells into M1 macrophages and plays important roles in the immune response.

Case report: The altered rate of monocytic cell death in a patient of Muckle-Wells syndrome with atypical clinical course.

Muckle-Wells syndrome (MWS) is an autosomal dominant autoinflammatory disease recognized as the intermediate phenotype of cryopyrin-associated periodic syndrome (CAPS) caused by NLRP3 gene mutation. It often takes a long time before the diagnosis is made because the clinical presentation of MWS is variable. We report a pediatric case who had had persistently elevated serum C-reactive protein (CRP) level since infancy and was diagnosed with MWS by the development of sensorineural hearing loss in school age. The patient had no periodic symptoms of MWS until the development of sensorineural hearing loss. It is important to differentiate MWS in patients with persistent serum CRP elevation, even if no periodic symptoms, including fever, arthralgia, myalgia and rash, are observed. Furthermore, in this patient, lipopolysaccharide (LPS)-induced monocytic cell death occurred, but to a lesser degree than has been reported in patients with chronic infantile neurological cutaneous, and articular syndrome (CINCA). Because CINCA and MWS are phenotypic variants on the same clinical spectrum, this suggests that a further large-scale study is desired to investigate the association between degree of monocytic cell death and disease severity in CAPS patients.

The immunoreceptor SLAMF8 promotes the differentiation of follicular dendritic cell-dependent monocytic cells with B cell-activating ability.

Follicular dendritic cells (FDCs) play a crucial role in generating high-affinity antibody-producing B cells during the germinal center (GC) reaction. Herein, we analysed the altered gene expression profile of a mouse FDC line, FL-Y, following lymphotoxin ß receptor stimulation, and observed increased Slam-family member 8 (Slamf8) mRNA expression. Forced Slamf8 expression and SLAMF8-Fc addition enhanced the ability of FL-Y cells to induce FDC-induced monocytic cell (FDMC) differentiation. FDMCs accelerated GC-phenotype proliferation in cultured B cells, suggesting that they are capable of promoting GC responses. Furthermore, a pulldown assay showed that SLAMF8-Fc could bind to SLAMF8-His. Overall, the homophilic interaction of SLAMF8 promotes FDMC differentiation and SLAMF8 might act as a novel regulator of GC responses by regulating FDMC differentiation.

Bioactive A-ring rearranged limonoids from the root barks of Walsura robusta.

Screening active natural products, rapid identification, and accurate isolation are of great important for modern natural lead compounds discovery1. We hereby reported the isolation of seven new neotecleanin-type limonoids (1-7), seven new limonoids with 5-oxatricyclo[5.4.0.11., 4.]hendecane ring system (8-14), and two new precursors (15-16) together with four known limonoids (17-20) from the root barks of Walsura robusta. Their structures, including their absolute configurations, were elucidated based on analyses of HR-ESI-MS, 1D/2D NMR, ECD spectrum calculations and single-crystal X-ray diffraction techniques. Compounds 2, 8, 9, 11, 13, 14, 18 showed significant anti-inflammatory activities in LPS-induced RAW 264.7 cell line, BV2 microglial cells, and Propionibacterium acnes-stimulated THP-1 human monocytic cells. Walrobsin M (11) exhibited anti-inflammatory activity with IC50 value of 7.96±0.36 µmol/L, and down-regulated phosphorylation levels of ERK and p38 in a dose-dependent manner.

Bioactive A-ring rearranged limonoids from the root barks of

Screening active natural products, rapid identification, and accurate isolation are of great important for modern natural lead compounds discovery. We hereby reported the isolation of seven new neotecleanin-type limonoids (-), seven new limonoids with 5-oxatricyclo[5.4.0.11., 4.]hendecane ring system (-), and two new precursors (-) together with four known limonoids (-) from the root barks of . Their structures, including their absolute configurations, were elucidated based on analyses of HR-ESI-MS, 1D/2D NMR, ECD spectrum calculations and single-crystal X-ray diffraction techniques. Compounds , , , , , , showed significant anti-inflammatory activities in LPS-induced RAW 264.7 cell line, BV2 microglial cells, and -stimulated THP-1 human monocytic cells. Walrobsin M () exhibited anti-inflammatory activity with IC value of 7.96±0.36 μmol/L, and down-regulated phosphorylation levels of ERK and p38 in a dose-dependent manner.

Comparative analysis of nanosystems' effects on human endothelial and monocytic cell functions.

The objective of our work was to investigate the effects of different types of nanoparticles on endothelial (HUVEC) and monocytic cell functions. We prepared and tested 14 different nanosystems comprising liposomes, lipid nanoparticles, polymer, and iron oxide nanoparticles. Some of the tested nanosystems contained targeting, therapeutic, or contrast agent(s). The effect of particles (0-400 µg/mL) on endothelial-monocytic cell interactions in response to TNF-α was investigated using an arterial bifurcation model and dynamic monocyte adhesion assay. Spontaneous HUVEC migration (0-100 µg/mL nanoparticles) and chemotaxis of monocytic cells towards MCP-1 in presence of particles (0-400 µg/mL) were determined using a barrier assay and a modified Boyden chamber assay, respectively. Lipid nanoparticles dose-dependently reduced monocytic cell chemotaxis and adhesion to activated HUVECs. Liposomal nanoparticles had little effect on cell migration, but one formulation induced monocytic cell recruitment by HUVECs under non-uniform shear stress by about 50%. Fucoidan-coated polymer nanoparticles (25-50 µg/mL) inhibited HUVEC migration and monocytic cell chemotaxis, and had a suppressive effect on monocytic cell recruitment under non-uniform shear stress. No significant effects of iron oxide nanoparticles on monocytic cell recruitment were observed except lauric acid and human albumin-coated particles which increased endothelial-monocytic interactions by 60-70%. Some of the iron oxide nanoparticles inhibited HUVEC migration and monocytic cell chemotaxis. These nanoparticle-induced effects are of importance for vascular cell biology and function and must be considered before the potential clinical use of some of the analyzed nanosystems in cardiovascular applications.

Sp1 mediates phorbol ester (PMA)-induced expression of membrane-bound guanylyl cyclase GC-A in human monocytic THP-1 cells.

Cyclic guanosine monophosphate (cGMP) is synthesized by two types of enzymes: particulate (membrane-bound) guanylyl cyclases (pGCs) and soluble (cytosolic) guanylyl cyclases (sGCs). sGCs are primarily activated by binding of nitric oxide to their prosthetic heme group while pGCs are activated by binding of peptide ligands to their extracellular domains. One of them, pGC type A (GC-A) is activated by atrial and brain natriuretic peptides (ANP and BNP, respectively). Human monocytes isolated from peripheral blood mononuclear cells have been found to display sGC expression without concomitant expression of GC-A. However, GC-A activity appears in monocytes under certain conditions but a molecular mechanism of GC-A expression is still poorly understood. In this report we show that phorbol ester (PMA) induces transcription of a gene encoding GC-A in human monocytic THP-1 cells. Moreover, we find that PMA-treated THP-1 cells raise cGMP content following treatment with ANP. Studies using pharmacological inhibitors of protein kinases suggest involvement of protein kinase C (PKC), mitogen extracellular kinases (MEK1/2), and extracellular signal-regulated kinases (ERK1/2) in PMA-induced expression of the GC-A encoding gene in THP-1 cells. Finally, we show that PMA stimulates binding of Sp1 transcription factor to GC-rich DNA sequences and mithramycin A (a selective Sp1 inhibitor) inhibits expression of the GC-A mRNA in PMA-treated THP-1 cells. Taken together, our findings suggest that the PMA-stimulated PKC and MEK/ERK signaling pathways induce Sp1-mediated transcription of the GC-A encoding gene in human monocytic THP-1 cells.

Diclofenac Inhibits 27-hydroxycholesterol-induced Differentiation of Monocytic Cells into Mature Dendritic Cells.

We investigated whether diclofenac could influence the development of antigen-presenting cells in an oxygenated cholesterol-rich environment by determining its effects on the 27-hydroxycholesterol (27OHChol)-induced differentiation of monocytic cells into mature dendritic cells (mDCs). Treatment of human THP-1 monocytic cells with diclofenac antagonized the effects of 27OHChol by attenuating dendrite formation and cell attachment and promoting endocytic function. Diclofenac inhibited the transcription and surface expression of the mDC markers of CD80, CD83, and CD88, and reduced the 27OHChol-induced elevation of surface levels of MHC class I and II molecules to the basal levels in a dose-dependent manner. It also reduced the expression of CD197, a molecule involved in DC homing and migration. These results indicate that diclofenac inhibits the differentiation of monocytic cells into mDCs, thereby potentially modulating adaptive immune responses in a milieu rich in cholesterol oxidation products.

Diclofenac Inhibits 27-hydroxycholesterol-induced Differentiation of Monocytic Cells into Mature Dendritic Cells

We investigated whether diclofenac could influence the development of antigen-presenting cells in an oxygenated cholesterol-rich environment by determining its effects on the 27-hydroxycholesterol (27OHChol)-induced differentiation of monocytic cells into mature dendritic cells (mDCs). Treatment of human THP-1 monocytic cells with diclofenac antagonized the effects of 27OHChol by attenuating dendrite formation and cell attachment and promoting endocytic function. Diclofenac inhibited the transcription and surface expression of the mDC markers of CD80, CD83, and CD88, and reduced the 27OHChol-induced elevation of surface levels of MHC class I and II molecules to the basal levels in a dose-dependent manner. It also reduced the expression of CD197, a molecule involved in DC homing and migration. These results indicate that diclofenac inhibits the differentiation of monocytic cells into mDCs, thereby potentially modulating adaptive immune responses in a milieu rich in cholesterol oxidation products.

Low-level expression of human ACAT2 gene in monocytic cells is regulated by the C/EBP transcription factors.

Acyl-coenzyme A:cholesterol acyltransferases (ACATs) are the exclusive intracellular enzymes that catalyze the formation of cholesteryl/steryl esters (CE/SE). In our previous work, we found that the high-level expression of human ACAT2 gene with the CpG hypomethylation of its whole promoter was synergistically regulated by two transcription factors Cdx2 and HNF1α in the intestine and fetal liver. Here, we first observed that the specific CpG-hypomethylated promoter was correlated with the low expression of human ACAT2 gene in monocytic cell line THP-1. Then, two CCAAT/enhancer binding protein (C/EBP) elements within the activation domain in the specific CpG-hypomethylation promoter region were identified, and the expression of ACAT2 in THP-1 cells was evidently decreased when the C/EBP transcription factors were knock-downed using RNAi technology. Furthermore, ChIP assay confirmed that C/EBPs directly bind to their elements for low-level expression of human ACAT2 gene in THP-1 cells. Significantly, the increased expressions of ACAT2 and C/EBPs were also found in macrophages differentiated from both ATRA-treated THP-1 cells and cultured human blood monocytes. These results demonstrate that the low-level expression of human ACAT2 gene with specific CpG-hypomethylated promoter is regulated by the C/EBP transcription factors in monocytic cells, and imply that the lowly expressed ACAT2 catalyzes the synthesis of certain CE/SE that are assembled into lipoproteins for the secretion.

Shell matters: Magnetic targeting of SPIONs and in vitro effects on endothelial and monocytic cell function.

Superparamagnetic iron oxide nanoparticles (SPIONs) are versatile and easily functionalized agents with high potential for diagnostic and therapeutic intravascular applications. In this study, we analyzed the responses of endothelial (ECs) and monocytic cells to three different types of SPIONs, in order to assess the influence of physico-chemical properties on the biological reactions to SPIONs. The following formulations were used: (1) Lauric acid-coated and BSA-stabilized SPION-1,(2) Lauric acid/BSA-coated SPION-2 and (3) dextran-coated SPION-3. SPION-1 were strongly internalized by ECs and reduced their viability in static conditions. Additionally, they had a dose-dependent inhibitory effect on monocytic cell chemotaxis to MCP-1, but did not affect monocytic cell recruitment by ECs. SPION-2 uptake was less pronounced, both in ECs and monocytic cells, and these particles were better tolerated by the vascular cells. Not being internalized by endothelial or monocytic cells, SPION-3 did not induce relevant effects on cell viability, motility or endothelial-monocytic cell interactions.Taken together, localized accumulation of circulating SPION under physiologic-like flow conditions and their cellular uptake depends on the physicochemical characteristics. Our findings suggest that SPION-2 are suitable for magnetic targeting of atherosclerotic plaques. Due to their excellent biocompatibility and low internalization, SPION-3 may represent a suitable imaging agent for intravascular applications.

Kinetics of IL-23 and IL-12 secretion in response to Toxoplasma gondii antigens from THP-1 monocytic cells.

IL-23 and IL-12 are structurally similar and critical for the generation of efficient cellular immune responses. Toxoplasma gondii induces a strong cell-mediated immune response. However, little is known about IL-23 secretion profiles in T. gondii-infected immune cells in connection with IL-12. We compared the patterns of IL-23 and IL-12 production by THP-1 human monocytic cells in response to stimulation with live or heat-killed T. gondii tachyzoites, or with equivalent quantities of either T. gondii excretory/secretory proteins (ESP) or soluble tachyzoite antigen (STAg). IL-23 and IL-12 were significantly increased from 6 hr after stimulation with T. gondii antigens, and their secretions were increased with parasite dose-dependent manner. IL-23 concentrations were significantly higher than those of IL-12 at the same multiplicity of infection. IL-23 secretion induced by live parasites was significantly higher than that by heat-killed parasites, ESP, or STAg, whereas IL-12 secretion by live parasite was similar to those of ESP or STAg. However, the lowest levels of both cytokines were at stimulation with heat-killed parasites. These data indicate that IL-23 secretion patterns by stimulation with various kinds of T. gondii antigens at THP-1 monocytic cells are similar to those of IL-12, even though the levels of IL-23 induction were significantly higher than those of IL-12. The detailed kinetics induced by each T. gondii antigen were different from each other.

Kinetics of IL-23 and IL-12 Secretion in Response to Toxoplasma gondii Antigens from THP-1 Monocytic Cells

IL-23 and IL-12 are structurally similar and critical for the generation of efficient cellular immune responses. Toxoplasma gondii induces a strong cell-mediated immune response. However, little is known about IL-23 secretion profiles in T. gondii-infected immune cells in connection with IL-12. We compared the patterns of IL-23 and IL-12 production by THP-1 human monocytic cells in response to stimulation with live or heat-killed T. gondii tachyzoites, or with equivalent quantities of either T. gondii excretory/secretory proteins (ESP) or soluble tachyzoite antigen (STAg). IL-23 and IL-12 were significantly increased from 6 hr after stimulation with T. gondii antigens, and their secretions were increased with parasite dose-dependent manner. IL-23 concentrations were significantly higher than those of IL-12 at the same multiplicity of infection. IL-23 secretion induced by live parasites was significantly higher than that by heat-killed parasites, ESP, or STAg, whereas IL-12 secretion by live parasite was similar to those of ESP or STAg. However, the lowest levels of both cytokines were at stimulation with heat-killed parasites. These data indicate that IL-23 secretion patterns by stimulation with various kinds of T. gondii antigens at THP-1 monocytic cells are similar to those of IL-12, even though the levels of IL-23 induction were significantly higher than those of IL-12. The detailed kinetics induced by each T. gondii antigen were different from each other.

Angiotensin II induces NF-κB, JNK and p38 MAPK activation in monocytic cells and increases matrix metalloproteinase-9 expression in a PKC- andRho kinase-dependent manner

Angiotensin II (ANG II), the main effector of the renin-angiotensin system, is implicated in endothelial permeability, recruitment and activation of the immune cells, and also vascular remodeling through induction of inflammatory genes. Matrix metalloproteinases (MMPs) are considered to be important inflammatory factors. Elucidation of ANG II signaling pathways and of possible cross-talks between their components is essential for the development of efficient inhibitory medications. The current study investigates the inflammatory signaling pathways activated by ANG II in cultures of human monocytic U-937 cells, and the effects of specific pharmacological inhibitors of signaling intermediates on MMP-9 gene (MMP-9) expression and activity. MMP-9 expression was determined by real-time PCR and supernatants were analyzed for MMP-9 activity by ELISA and zymography methods. A multi-target ELISA kit was employed to evaluate IκB, NF-κB, JNK, p38, and STAT3 activation following treatments. Stimulation with ANG II (100 nM) significantly increased MMP-9 expression and activity, and also activated NF-κB, JNK, and p38 by 3.8-, 2.8- and 2.2-fold, respectively (P < 0.01). ANG II-induced MMP-9 expression was significantly reduced by 75 and 67 percent, respectively, by co-incubation of the cells with a selective inhibitor of protein kinase C (GF109203X, 5 µM) or of rho kinase (Y-27632, 15 µM), but not with inhibitors of phosphoinositide 3-kinase (wortmannin, 200 nM), tyrosine kinases (genistein, 100 µM) or of reactive oxygen species (α-tocopherol, 100 µM). Thus, protein kinase C and Rho kinase are important components of the inflammatory signaling pathways activated by ANG II to increase MMP-9 expression in monocytic cells. Both signaling molecules may constitute potential targets for effective management of inflammation.

Angiotensin II Differentially Induces Matrix Metalloproteinase-9 and Tissue Inhibitor of Metalloproteinase-1 Production and Disturbs MMP/TIMP Balance.

Angiotensin II, the main component of the renin-angiotensin system, is associated with cardiovascular diseases such as hypertension, vascular remodeling and inflammation. Remodeling process results from dysregulation of Matrix Metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). MMPs are considered as important target genes for angiotensin II. The aim of this study was to determine the effects of angiotensin II on MMP-9 and TIMP-1 production and MMP/TIMP balance in a monocytic cell type. Human monocytic U-937 cells were cultured and treated with 100 nM angiotensin II. Supernatants were analyzed for MMP-9 and TIMP-1 using ELISA and zymography methods. Real-time PCR was utilized to evaluate relative MMP-9 and TIMP-1 genes expression following treatments. Cytotoxicity potentials of treatments were determined by assaying lactate dehydrogenase leakage from the cells. Stimulation of the monocytic cells with angiotensin II significantly increased MMP-9 and TIMP-1 secretion as measured by ELISA (p < 0.05). It also augmented gelatinolytic activity of MMP-9 in the conditioned media as much as 49% (p < 0.05). Incubation of the cells with angiotensin II for 12 hr increased MMP-9 and TIMP-1 gene expression 2.7 and 1.8 folds, respectively (p < 0.05). Angiotensin II treatments did not establish significant cytotoxic effects. In summary, our data provide further evidences that monocytic MMP-9 is a major effector of angiotensin II. It is induced more efficiently than TIMP-1 by angiotensin II that leads to MMP/TIMP imbalance. Our data also reveal the pivotal participation of these cells in pathological cardiovascular remodeling mediated by angiotensin II.