Dexamethasone Suppresses Oxysterol-Induced Differentiation of Monocytic Cells

27-Hydroxycholesterol induces expression of zonula occludens-1 in monocytic cells via multiple kinases pathways

Zonula occludens (ZO)-1, a tight-junction protein (TJP), is expressed in dendritic cells (DCs) but not in monocytes, and 27-hydroxycholesterol (27OHChol) drives the differentiation of monocytes into DCs. Because the effects of 27OHChol on ZO-1 are not yet clearly defined, we investigated whether 27OHChol induces expression of the TJP. The treatment of human THP-1 monocytic cells with 27OHChol resulted in the elevated transcript levels of ZO-1 but not of ZO-2 or -3. 27OHChol increased the total amount of ZO-1 protein in the cells as well as its level on the cells surface. Cholesterol, however, did not influence expression of ZO-1. And, the expression of ZO-1 protein was mediated by endoplasmic reticulum (ER)-to-Golgi body transport system. Pharmacological kinase inhibition with LY294002 (a PI3K inhibitor), U0126 (a MEK/ERK inhibitor), or PP2 (a Src family kinase inhibitor) resulted in impaired ZO-1 expression at both transcript and protein levels. Drugs that are reported to suppress DC differentiation also inhibited 27OHChol-mediated expression and the localization of ZO-1, indicating the coincidence of ZO-1 upregulation and DC differentiation. These results suggest that ZO-1 is differentially expressed while monocytes differentiate into DCs in the presence of 27OHChol via pathways in which distinct signaling molecules are involved.

Impact of Oxysterols on Cell Death, Proliferation, and Differentiation Induction: Current Status

Oxysterols are oxidized derivatives of cholesterol produced by enzymatic activity or non-enzymatic pathways (auto-oxidation). The oxidation processes lead to the synthesis of about 60 different oxysterols. Several oxysterols have physiological, pathophysiological, and pharmacological activities. The effects of oxysterols on cell death processes, especially apoptosis, autophagy, necrosis, and oxiapoptophagy, as well as their action on cell proliferation, are reviewed here. These effects, also observed in several cancer cell lines, could potentially be useful in cancer treatment. The effects of oxysterols on cell differentiation are also described. Among them, the properties of stimulating the osteogenic differentiation of mesenchymal stem cells while inhibiting adipogenic differentiation may be useful in regenerative medicine.

Reblastatins Inhibit Phenotypic Changes of Monocytes/Macrophages in a Milieu Rich in 27-Hydroxycholesterol

We investigated effects of reblastatins on phenotypic changes in monocytes/macrophages induced by 27-hydroxycholesterol (27OHChol). Treatment of THP-1 monocytic cells with reblastatin derivatives, such as 17-demethoxy-reblastatin (17-DR), 18-dehydroxyl-17-demethoxyreblastatin (WK88-1), 18-hydroxyl-17-demethoxyreblastatin (WK88-2), and 18-hydroxyl-17-demethoxy-4,5-dehydroreblastatin (WK88-3), resulted in blockage of CCL2, CCL3, and CCL4 expression at the transcription and protein levels, which, in turn, impaired migration of monocytes/macrophages and Jurkat T cells expressing CCR5, and almost complete inhibition of transcription of M1 marker cytokines, like CXCL10, CXCL11, and TNF-α. Reblastatins also downregulated surface CD14 as well as soluble CD14 along with inhibition of LPS response and matrix metalloprotease-9 expression. Surface levels of mature dendritic cell (mDC)-specific markers, including CD80, CD83, CD88, CD197, and MHC class I and II molecules, were remarkably down-regulated, and 27OHChol-induced decrease of endocytic activity was recovered following treatment with 17-DR, WK88-1, WK88-2, and WK88-3. However, 15-hydroxyl-17-demethoxyreblastatin (DHQ3) did not affect the molecular or functional changes in monocytic cells induced by 27OHChol. Furthermore, surface levels of CD105, CD137, and CD166 were also down-regulated by 17-DR, WK88-1, WK88-2, and WK88-3, but not by DHQ3. Collectively, results of the current study indicate that, except DHQ3, reblastatins regulate the conversion and differentiation of monocytic cells to an immunostimulatory phenotype and mDCs, respectively, which suggests possible applications of reblastatins for immunomodulation in a milieu rich in oxygenated cholesterol molecules.

Prednisolone suppresses the immunostimulatory effects of 27-hydroxycholesterol

In cholesterol-fed rabbits, site-specific targeting of prednisolone nanoparticles results in significantly reduced neo-intimal inflammation with a decreased infiltration of monocytes/macrophages. To understand the molecular mechanisms underlying this, the current study investigated whether prednisolone affects the immune attributes of 27-hydroxycholesterol (27OHChol), the major oxidized cholesterol molecule in circulation and tissue, in human (THP-1) monocyte/macrophage cells. THP-1 cells were exposed to 27OHChol in the presence of prednisolone followed by evaluation of inflammatory molecules at mRNA and protein levels by quantitative PCR, western blotting, ELISA and flow cytometry. The results revealed that prednisolone suppressed the 27OHChol-mediated expression of various macrophage (M)1 markers, including chemokine ligand 2, C-X-C chemokine motif 10, tumor necrosis factor-α and CD80. Treatment also impaired the 27OHCHol-enhanced migration of monocytic cells, downregulated the 27OHChol-induced cell surface expression of CD14 and inhibited the release of soluble CD14 comparable with a weakened lipopolysaccharide response. Furthermore, prednisolone suppressed the 27OHChol-induced expression of matrix metalloproteinase 9 at the transcriptional and protein level, as well as the phosphorylation of the p65 subunit. Prednisolone increased the transcription of CD163 and CD206 genes, and augmented the 27OHChol-induced transcription of CD163 without upregulating the 27OHChol-induced surface protein level of the gene. The results indicated that prednisolone inhibited the polarization of monocytes/macrophages towards the M1 phenotype, which that the immunostimulatory effects of 27OHCHol were being regulated and the immune responses in conditions that were rich in oxygenated cholesterol molecules were being modulated.

Correlation of Leukocyte Subtypes, Neutrohyl Lymphocyte Ratio, and Functional Outcome in Brain Metastasis

BACKGROUND:

As the most cause of death in patients with solid extracranial malignancy, brain metastasis (BM) nowadays being studied extensively especially on how to find a reliable laboratory marker that can correlate with its clinical outcome. Leukocyte subtypes, primarily neutrophils and lymphocytes and its ratio known as Neutrophils-Lymphocyte Ratio (NLR) have been known before its relationship with progressivity of BM from other solid tumours.

AIM:

The objectives of this research to study the correlation of leukocyte subtypes, neutrophil-lymphocyte ratio & functional outcome in brain metastasis.

METHODS:

The study subjects were recruited consecutively from the study population. Venous blood was taken 5 ml of venous blood samples done in the first day of admission on emergency department and neurology clinic of Neurology Department of Adam Malik General Hospital before any drug injections. Samples were kept in vacutainer tubes containing ethylenediaminetetraacetic acid (EDTA) and sent to Department of Clinical Pathology laboratory of Adam Malik General Hospital, immediately centrifuged at 3100 rpm for 10 minutes in -20°C temperature and analysed using Sysmex XT-2000i. Functional outcome of the patient assessed using Karnofsky performance scale (KPS) in a cross-sectional manner with laboratory analysis.

RESULTS:

We conduct a mean differences and correlational leukocytes and its subsets analysis of 72 BM patients resulting on significant positive correlation on lymphocyte percentage (r = 0.383, p = 0.001) and lymphocyte absolute (r = 0.265, p = 0.024), also significant negative correlation on neutrophils (r = -0.240, p = 0.042) and NLR (r = -0.432, p < 0.001) with Karnofsky Performance Scale (KPS).

CONCLUSION:

Increased lymphocyte absolute and lymphocyte percentage correlated significantly (p < 0.05) with better KPS, while elevated neutrophils percentage and increased NLR show significant correlation with worse outcome of BM patients.

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.