The expression of the receptor for advanced glycation end-products (RAGE) in RA-FLS is induced by IL-17 via Act-1

Introduction

The receptor for advanced glycation end-products (RAGE) has been implicated in the pathogenesis of arthritis. We conducted this study to determine the effect of interleukin (IL)-17 on the expression and production of RAGE in fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA). The role of nuclear factor-κB (NF-κB) activator 1 (Act1) in IL-17-induced RAGE expression in RA-FLS was also evaluated.

Methods

RAGE expression in synovial tissues was assessed by immunohistochemical staining. RAGE mRNA production was determined by real-time polymerase chain reaction. Act-1 short hairpin RNA (shRNA) was produced and treated to evaluate the role of Act-1 on RAGE production.

Results

RAGE, IL-17, and Act-1 expression increased in RA synovium compared to osteoarthritis synovium. RAGE expression and production increased by IL-17 and IL-1β (*P <0.05 vs. untreated cells) treatment but not by tumor necrosis factor (TNF)-α in RA-FLS. The combined stimuli of both IL-17 and IL-1β significantly increased RAGE production compared to a single stimulus with IL-17 or IL-1β alone (P <0.05 vs. 10 ng/ml IL-17). Act-1 shRNA added to the RA-FLS culture supernatant completely suppressed the enhanced production of RAGE induced by IL-17.

Conclusions

RAGE was overexpressed in RA synovial tissues, and RAGE production was stimulated by IL-17 and IL-1β. Act-1 contributed to the stimulatory effect of IL-17 on RAGE production, suggesting a possible inhibitory target for RA treatment.     

Tolerance of <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> K35 to lignocellulose-derived inhibitory compounds

The hydrolysis which converts polysaccharides to the fermentable sugars for yeast’s lingocellulosic ethanol production also generates byproducts which inhibit the ethanol production. To investigate the extent to which inhibitory compounds affect yeast’s growth and ethanol production, fermentations by Saccharomyces cerevisiae K35 were investigated in various concentrations of acetic acid, furfural, 5-hydroxymethylfurfural (5-HMF), syringaldehyde, and coumaric acid. Fermentation in hydrolysates from yellow poplar and waste wood was also studied. After 24 h, S. cerevisiae K35 produced close to theoretically predicted ethanol yields in all the concentrations of acetic acid tested (1 ∼ 10 g/L). Both furans and phenolics inhibited cell growth and ethanol production. Ethanol yield, however, was unaffected, even at high concentrations, except in the cases of 5 g/L of syringaldehyde and coumaric acid. Although hydrolysates contain various toxic compounds, in their presence, S. Cerevisiae K35 consumed close to all the available glucose and yielded more ethanol than theoretically predicted. S. Cerevisiae K35 was demonstrated to have high tolerance to inhibitory compounds and not to need any detoxification for ethanol production from hydrolysates.     

Embryonic stem-cell-preconditioned microenvironment induces loss of cancer cell properties in human melanoma cells

The cancer microenvironment affects cancer cell proliferation and growth. Embryonic stem (ES)-preconditioned 3-dimensional (3-D) culture of cancer cells induces cancer cell reprogramming and results in a change in cancer cell properties such as differentiation and migration in skin melanoma. However, the mechanism has not yet been clarified. Using the ES-preconditioned 3-D microenvironment model, we provide evidence showing that the ES microenvironment inhibits proliferation and anchorage-independent growth of SK-MEL-28 melanoma cells. We also found that the ES microenvironment suppresses telomerase activity and thereby induces senescence in SK-MEL-28 cells. Furthermore, we observed that gremlin, an antagonist of BMP4, is secreted from ES cells and plays an important role in cellular senescence. Knocking down gremlin in the ES microenvironment increases proliferation and anchorage-independent growth of SK-MEL-28 melanoma cells. Taken together, these results demonstrated that gremlin is a crucial factor responsible for abrogating melanoma properties in the ES-preconditioned 3-D microenvironment.     

Enhancement of centelloside production from cultured plants of Centella asiatica by combination of thidiazuron and methyl jasmonate

In order to produce centellosides from whole plant cultures of Centella asiatica (L.) Urban, we evaluated the synergistic effects of thidiazuron (TDZ) and methyl jasmonate (MJ) on whole plant growth and centelloside production. After 4 weeks of treatment with 0.025 mg/L of TDZ coupled with 0.1 mM MJ, the production of madecassoside and asiaticoside from whole plant cultures was estimated to be 2.40- and 2.44-fold, respectively, above that of MJ elicitation alone. When whole plants were treated with a growth regulator and an elicitor, the growth of whole plants, as compared to the controls, did not differ. Additionally, total phytosyterol content in the leaves of whole plants co-treated with MJ and TDZ was 1.08-fold greater than those of MJ alone. These results demonstrate that combined treatments not only stimulate the accumulation of centellosides in the leaves but also inhibit the reduction of phytosterol levels caused by MJ elicitation.     

DNA methyltransferase 3b regulates nerve growth factor-induced differentiation of PC12 cells by recruiting histone deacetylase 2

To elucidate the role of epigenetic reprogramming in cell- or tissue-specific differentiation, we explored the role of DNA methyltransferases (Dnmts) in the nerve growth factor (NGF)-induced differentiation of PC12 (pheochromocytoma) cells into neuronal cells. The mRNA and protein levels of de novo methyltransferase Dnmt3b increased, whereas those of Dnmt3a and Dnmt1 decreased, during NGF-induced neurite outgrowth. Dnmt3b localized in the nucleus, as well as in the growing neurites. When the expression of Dnmt3b was inhibited by antisense or small interfering RNA, PC12 cells continued to proliferate and failed to generate neurites. Cells depleted of Dnmt3b were unable to exit the cell cycle even after 6 days of NGF treatment. Furthermore, this failure in differentiation correlated with significant attenuation in tyrosine phosphorylation of TrkA (a marker for NGF-induced differentiation) and reduced the expression of neuronal markers, Hu antigen, and MAP2. The methyl-CpG content of the PC12 genome or the methylation status of repetitive elements was not significantly altered after differentiation and was not affected by Dnmt3b depletion. This was consistent with the ability of the catalytic-site mutant of Dnmt3b to induce differentiation in Dnmt3b-depleted cells after NGF treatment. The Dnmt3b-mediated differentiation was attributed to its N-terminal domain, which recruits histone deacetylase 2 (Hdac2), as demonstrated by (i) impeding of differentiation by the Hdac inhibitors, (ii) facilitation of the differentiation process by overexpression of the N-terminal domain of Dnmt3b, (iii) higher Hdac activity associated with Dnmt3b after NGF treatment, and (iv) coimmunoprecipitation and cosedimentation of Dnmt3b specifically with Hdac2 in a glycerol density gradient. These data indicate a novel role of Dnmt3b in neuronal differentiation.     

CNS midline cells contribute to maintenance of the initial dorsoventral patterning of the Drosophila ventral neuroectoderm

Dorsoventral patterning of the Drosophila ventral neuroectoderm is established by the expression of three evolutionarily conserved homeodomain genes: ventral nervous system defective (vnd), intermediate neuroblasts defective (ind), and muscle segment homeobox (msh) in the medial, intermediate, and lateral columns of the ventral neuroectoderm, respectively. It was not clear whether extrinsic factor(s) from the CNS midline cells influence the initial dorsoventral patterning by controlling the expression of the dorsoventral patterning genes. We show here that the CNS midline cells, specified by single-minded (sim), are essential for maintaining expression of the dorsoventral patterning genes. Ectopic expression of sim in the ventral neuroectoderm during the blastoderm stage repressed expression of the three homeodomain genes in the ventral neuroectoderm. This indicates that the identity of the CNS midline cells is established by a series of repressions of the three homeodomain genes in the ventral neuroectoderm. Ectopic expression of sim in the ventral neuroectoderm during initial neurogenesis induced ectopic ind expression in the medial column in addition to that in the intermediate column via EGFR signaling between the ventral neuroectoderm and midline cells. In contrast, it repressed the expression of vnd and msh in the medial and lateral columns, respectively. Our findings demonstrate that the CNS midline cells provide extrinsic positional information via EGFR signaling that maintains the initial subdivision of the ventral neuroectoderm into three dorsoventral columns during initial neurogenesis.