27-Hydroxycholesterol induces macrophage gene expression via LXR-dependent and -independent mechanisms.

27-Hydroxycholesterol (27OHChol) exhibits agonistic activity for liver X receptors (LXRs). To determine roles of the LXR agonistic activity in macrophage gene expression, we investigated the effects of LXR inhibition on the 27OHChol-induced genes. Treatment of human THP-1 cells with GSK 2033, a potent cell-active LXR antagonist, results in complete inhibition in the transcription of LXR target genes (such as LXRα and ABCA1) induced by 27OHChol or a synthetic LXR ligand TO 901317. Whereas expression of CCL2 and CCL4 remains unaffected by GSK 2033, TNF-α expression is further induced and 27OHChol-induced CCL3 and CXCL8 genes are suppressed at both the transcriptional and protein translation levels in the presence of GSK 2033. This LXR antagonist downregulates transcript levels and surface expression of CD163 and CD206 and suppresses the transcription of CD14, CD80, and CD86 genes without downregulating their surface levels. GSK 2033 alone had no effect on the basal expression levels of the aforementioned genes. Collectively, these results indicate that LXR inhibition leads to differential regulation of 27-hydroxycholesterolinduced genes in macrophages. We propose that 27OHChol induces gene expression and modulates macrophage functions via LXR-dependent and -independent mechanisms.

Sildenafil protects neuronal cells from mitochondrial toxicity induced by ß-amyloid peptide via ATP-sensitive K+ channels.

To understand the molecular mechanisms underlying the beneficial effects of sildenafil in animal models of neurological disorders, we investigated the effects of sildenafil on the mitochondrial toxicity induced by ß-amyloid (Aß) peptide. Treatment of HT-22 hippocampal neuronal cells with Aß25∼35 results in increased mitochondrial Ca2+ load, which is subsequently suppressed by sildenafil as well as by diazoxide, a selective opener of the ATP-sensitive K+ channels (KATP). However, the suppressive effects of sildenafil and diazoxide are significantly attenuated by 5-hydroxydecanoic acid (5-HD), a KATP inhibitor. The increased mitochondrial Ca2+ overload is accompanied by decrease in the intracellular ATP concentration, increase in intracellular ROS generation, occurrence of mitochondrial permeability transition, and activation of caspase-9 and cell death. Exposure to sildenafil inhibited the mitochondria-associated changes and cell death induced by Aß. However, the inhibitory effects of sildenafil are abolished or weakened in the presence of 5-HD, suggesting that opening of the mitochondrial KATP is required for sildenafil to exert these effects. Taken together, these results indicate that at the mitochondrial levels, sildenafil plays a protective role towards neuronal cell in an environment rich in Aß, and exerts its effects via the mitochondrial KATP channels-dependent mechanisms.

7-Oxygenated cholesterol molecules differentially affect the expression of zonula occludens-1 in vascular smooth muscle cells and monocyte/macrophage cells.

To investigate the effects of 7-oxygenated cholesterol molecules on the expression of tight junction proteins, we examined the outcomes effects of 7-ketocholesterol (7K), 7α-hydroxycholesterol (7αOHChol) and 7ß-hydroxycholesterol (7ßOHChol) on the expression of the tight-junction protein zonula occludens-1 (ZO-1) using vascular cells. Vascular smooth muscle cells (VSMCs) constitutively express ZO-1, and this expression remained unaffected in the presence of cholesterol. However, the level of ZO-1 protein decreased after exposure to 7K and, to a lesser extent, 7αOHChol and 7ßOHChol. ZO-1 was translocated to the nucleus following treatment with 7K; this translocation was inhibited by z-VAD-fmk, a pan-caspase inhibitor. ZO-1 protein was found to disintegrate in the aorta of ApoE knockout mice fed a high cholesterol diet, whereas it remained intact in the wild-type control. THP-1 monocyte/macrophage cells, which show no expression of ZO-1, were not influenced by treatment with cholesterol, 7K, and 7ßOHChol. However, the treatment of THP-1 cells with 7αOHChol resulted in ZO-1 expression, which largely remained localized on the cytoplasmic membrane. These results indicate the varying effects of 7-oxygenated cholesterol molecules on the expression and localization of ZO-1 depending on cell types, and suggest the contribution of 7-oxygeneted cholesterol molecules to the structural alteration of tight junctions.

PI3K and ERK signaling pathways are involved in differentiation of monocytic cells induced by 27-hydroxycholesterol.

27-Hydroxycholesterol induces differentiation of monocytic cells into mature dendritic cells, mDCs. In the current study we sought to determine roles of the PI3K and the ERK pathways in the 27OHChol-induced differentiation. Up-regulation of mDC-specific markers like CD80, CD83 and CD88 induced by stimulation with 27OHChol was significantly reduced in the presence of LY294002, an inhibitor of PI3K, and U0126, an inhibitor of ERK. Surface expression of MHC class I and II molecules elevated by 27OHChol was decreased to basal levels in the presence of the inhibitors. Treatment with LY294002 or U0126 resulted in recovery of endocytic activity which was reduced by 27OHChol. CD197 expression and cell adherence enhanced by 27OHChol were attenuated in the presence of the inhibitors. Transcription and surface expression of CD molecules involved in atherosclerosis such as CD105, CD137 and CD166 were also significantly decreased by treatment with LY294002 and U0126. These results mean that the PI3K and the ERK signaling pathways are necessary for differentiation of monocytic cells into mDCs and involved in over-expression of atherosclerosis-associated molecules in response to 27OHChol.

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.

Oxime derivative TFOBO promotes cell death by modulating reactive oxygen species and regulating NADPH oxidase activity in myeloid leukemia.

Several derivatives derived from the oxime structure have been reported as potential anticancer agents in various cancers. Here, we first tested a novel oxime-containing derivative of 2-((2,4,5-trifluorobenzyl)oxy)benzaldehyde oxime (TFOBO) to evaluate its anticancer effect in myeloid leukemic cells. Compared to (2-((2,4,5-trifluorobenzyl)oxy)phenyl)methanol (TFOPM), the oxime derivative TFOBO suppresses leukemic cell growth by significantly increasing reactive oxygen species (ROS) levels and cell death. Leukemic cells treated with TFOBO displayed apoptotic cell death, as indicated by nuclear condensation, DNA fragmentation, and annexin V staining. TFOBO increases Bax/Bcl2 levels, caspase9, and caspase3/7 activity and decreases mitochondrial membrane potential. ROS production was reduced by N-acetyl-L-cysteine, a ROS scavenger, diphenyleneiodonium chloride, a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, after exogenous TFOBO treatment. ROS inhibitors protect leukemic cells from TFOBO-induced cell death. Thus, our study findings suggest that TFOBO promotes apoptosis by modulating ROS and regulating NADPH oxidase activity. Collectively, the oxime-containing derivative TFOBO is a novel therapeutic drug for myeloid leukemia.

Miconazole Suppresses 27-Hydroxycholesterol-induced Inflammation by Regulating Activation of Monocytic Cells to a Proinflammatory Phenotype.

Miconazole is effective in treating inflammatory skin conditions and has well-established antifungal effects. To elucidate the underlying mechanisms mediating its additional beneficial effects, we assessed whether miconazole influences the inflammation induced by 27-hydroxycholesterol (27OHChol), an oxygenated cholesterol derivative with high proinflammatory activity, using THP-1 monocytic cells. Miconazole dose-dependently inhibited the expression of proinflammatory markers, including CCL2 and CCR5 ligands such as CCL3 and CCL4, and impaired the migration of monocytic cells and CCR5-positive T cells. In the presence of 27OHChol, miconazole decreased CD14 surface levels and considerably weakened the lipopolysaccharide response. Furthermore, miconazole blocked the release of soluble CD14 and impaired the transcription of the matrix metalloproteinase-9 gene and secretion of its active gene product. Additionally, it downregulated the expression of ORP3 and restored the endocytic function of THP-1 cells. Collectively, these findings indicate that miconazole regulates the 27OHChol-induced expression of proinflammatory molecules in monocytic cells, thereby suppressing inflammation in an oxysterol-rich milieu.

Cyclosporin A inhibits differentiation and activation of monocytic cells induced by 27-hydroxycholesterol.

27-Hydroxycholesterol (27OHChol) is a bioactive molecule that induces monocytic cell activation and differentiation and thereby participates in immune responses under hypercholesterolemic condition. However, it is unknown whether cyclosporin A (CsA), an immunosuppressant, affects biological effects of 27OHChol. In this study, we investigated whether CsA alters 27OHChol-induced cellular and molecular responses using the human monocyte/macrophage THP-1 cells. Treatment of the cells with CsA resulted in decreased expression of the mDC-specific markers (CD80, CD83 and CD88) induced by 27OHChol. Reduced endocytic activity recovered in the presence of CsA. The drug also inhibited the expressions of MHC class I and II molecules and CD197, a homing molecule of mDCs. We further investigated the outcomes of CsA treatment on the expression of M1 polarization markers and CD14, a component of the innate immune system. The drug decreased transcript levels of genes associated with the M1 polarization of monocytic cells, including CCL2, as well as expression of CD14 and MMP-9 which is involved in soluble CD14 shedding. Taken together, these results indicate that CsA inhibits the 27OHChol-induced differentiation and activation of monocytic cells into a mature dendritic cell (mDC) type and an immuno-stimulatory M1 subset, respectively, thereby modifying immune responses in a milieu rich in cholesterol and oxidized cholesterol molecules.

Giant Sellar Xanthogranuloma after Surgical Treatment of Symptomatic Rathke's Cleft Cyst.

Extremely massive sellar xanthogranuloma (XG) are rare, and the surgical outcome and prognosis are not well known. XG remain unknown whether they are derived from Rathke's cleft cysts (RCCs) or craniopharyngiomas (CPs) following extensive inflammation and metaplasia, to the point that no epithelium is readily identifiable. These lesions usually tend to occur in younger patients (mean 28.3 years), have a smaller diameter, and remain primarily intrasellar region with infrequent calcification. This 36-year-old man presented our hospital with visual deterioration. At the time of visit, there were no neurological problems other than visual field defect and hormonal disorder. He visited our hospital in 2007 due to headache and decreased vision, and underwent transphenoid surgery for pituitary RCC. Since then, he has received treatment at our hospital for postoperative hormonal disorders. Through preoperative imaging study, the author suspected CP and underwent surgery. During the operation, the adhesion of the tumor to the surrounding major neurovascular structures was severe in the naked eyes, but the tumor could be removed more easily than expected. The postoperative histological findings were confirmed as XG. The postoperative course was uneventful. Compared to the previous literature, this case is a case where the size of XG is very large in a sellar region and it can be proved that it originated from the RCC. And regular follow-up is necessary to confirm the prognosis after surgery.

7α-Hydroxycholesterol induces monocyte/macrophage cell expression of interleukin-8 via C5a receptor.

We investigated effects of 7-oxygenated cholesterol derivatives present in atherosclerotic lesions, 7α-hydroxycholesterol (7αOHChol), 7ß-hydroxycholesterol (7ßOHChol), and 7-ketocholesterol (7K), on IL-8 expression. Transcript levels of IL-8 and secretion of its corresponding gene product by monocytes/macrophages were enhanced by treatment with 7αOHChol and, to a lesser extent, 7K, but not by 7ßOHChol. The 7-oxygenated cholesterol derivatives, however, did not change transcription of the IL-8 gene in vascular smooth muscle cells. 7αOHChol-induced IL-8 gene transcription was inhibited by cycloheximide and Akt1 downregulation, but not by OxPAPC. Expression of C5a receptor was upregulated after stimulation with 7αOHChol, but not with 7K and 7ßOHChol, and a specific antagonist of C5a receptor inhibited 7αOHChol-induced IL-8 gene expression in a dose dependent manner. Pharmacological inhibitors of PI3K and MEK almost completely inhibited expression of both IL-8 and cell-surface C5a receptor induced by 7αOHChol. These results indicate that 7-oxygenated cholesterol derivatives have differential effects on monocyte/macrophage expression of IL-8 and C5a receptor and that C5a receptor is involved in 7αOHChol-induced IL-8 expression via PI3K and MEK.

The Pterional-Transsylvian Approach for Tumor in the Temporal Horn: A Case Report.

A variety of surgical approaches to temporal horn tumors of the lateral ventricle have been described. Magnetic resonance imaging (MRI) and angiography are the preferred modalities for preoperative evaluation and provide important information for the choice of surgical approach. A 59-year-old man was referred to our hospital due to confusion and gait disturbance. On enhanced MRI, a homogeneous enhanced solitary mass was observed within the temporal horn of the left lateral ventricle with transependymal extension. The lesion was accompanied by increased hypervascular tumor blush on preoperative cerebral angiography. Subtotal removal of the temporal horn tumor was performed because the lesion was identified as lymphoma during surgery. The postoperative course was un-eventful. The patient was referred to the oncology department for conventional chemotherapy. Adjuvant chemotherapy improved the clinical outcome. The pterional-transsylvian approach was beneficial for partial removal of the tumor and tissue diagnosis in this case.

An unusual cervical spinal meningioma in a child.

The incidence of spinal meningioma is very rare in children. A 14-year-old girl presented with right arm weakness, gait disturbance, and urinary incontinence. Cervical magnetic resonance imaging revealed an intradural extramedullary tumor dorsal to the spinal cord in the level of C1. The tumor was totally removed despite the severe cord compression. Meningotheliomatous meningioma was diagnosed after histological examination.