Anti-inflammatory action of Cudrania tricuspidata on spleen cell and T lymphocyte proliferation

This study examined whether an extract of Cudrania tricuspidata shows anti-proliferative effects in anti-CD3/CD28-mediated spleen and CD4+CD25− T cells and decreases the production of the pro-inflammatory cytokines interleukin-2 (IL-2) and interferon-γ (IFN-γ) in anti-CD3/CD28-mediated CD4+CD25− T cells. The proliferation of anti-CD3/CD28-mediated spleen cells and CD4+CD25− T cells was effectively suppressed by C. tricuspidata. This extract, however, did not show cytotoxicity in spleen cells under conditions where the antigen was not stimulated using CCK-8 analysis. C. tricuspidata also decreased the production of the pro-inflammatory cytokines IL-2 and IFN-γ by selective inhibition of this extract on proliferating cells in anti-CD3/CD28-mediated CD4+CD25− T cells. These results suggest that C. tricuspidata may be useful in the treatment of autoimmune diseases and organ transplantation through the inhibitory action of T cells in inflammation.

In-vitro and in-vivo anti-allergic actions of Arecae semen

The effects of various extracts from oriental medicinal herbs on mast cell-mediated allergic reactions have been investigated. Among the extracts, Arecae semen was the most potent inhibitor of antigen-induced degranulation in RBL-2H3 mast cells. A. semen inhibited DNP-BSA- and compound 48/80-induced degranulation in RBL-2H3 mast cells with IC50 values of approximately 53 and 52 μg mL−1, respectively, and inhibited compound 48/80-induced systemic anaphylaxis by 46% at 300 mg kg−1 in mice. A. semen also inhibited the expression of TNF-α and the activation of mitogen activated protein kinase, ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of the activating phosphorylation of ERK1/2. These results suggest that A. semen may be useful for the treatment of various immediate and delayed allergic diseases.

Two-dimensional confinement of 3d{1} electrons in LaTiO_{3}/LaAlO{3} multilayers

We report spectroscopic ellipsometry measurements of the anisotropy of the interband transitions parallel and perpendicular to the planes of (LaTiO3)n(LaAlO3)5 multilayers with n=1-3. These provide direct information about the electronic structure of the two-dimensional (2D) 3d{1} state of the Ti ions. In combination with local density approximation, including a Hubbard U calculation, we suggest that 2D confinement in the TiO2 slabs lifts the degeneracy of the t{2g} states leaving only the planar d{xy} orbitals occupied. We outline that these multilayers can serve as a model system for the study of the t{2g} 2D Hubbard model.

Anti-inflammatory effects of Artemisia princeps in antigen-stimulated T cells and regulatory T cells

Objectives

The aim was to investigate the anti-inflammatory effects of Artemisia princeps extract on the activity of anti-CD3/CD28-stimulated CD4+CD25- T cells and antigen-expanded regulatory T cells.

Methods

CD4+CD25- T cells were activated with coated anti-CD3 and anti-CD28 and cultured in the presence or absence of various concentrations of A. princeps extract. The cultures were pulsed on Day 6 with [3H]thymidine and, after harvesting the cells, [3H] thymidine incorporation was measured. For analysis of interleukin-2 and interferon-γ secreted from CD4+CD25- T cells, culture supernatants were collected on Days 2 and 6. For the analysis of interleukin-10 secreted from the CD4+CD25- T cells and expanded regulatory T cells, supernatants were collected after 2 and 7 days, respectively. Cytokine levels were determined using an enzyme-linked immunosorbent assay. Potential medicinal components of the A. princeps extract were determined using gas chromatography–mass spectrometry.

Key findings

A. princeps (30 μg/ml) effectively suppressed proliferation of CD4+CD25- T cells that were stimulated with anti-CD3/CD28 without causing cytotoxicity in spleen cells incubated under conditions lacking antigen stimulation. A. princeps inhibited production of the pro-inflammatory cytokines interleukin-2 and interferon-γ in anti-CD3/CD28-stimulated CD4+CD25- T cells. Also, the extract slightly increased production of the anti-inflammatory cytokine interleukin-10 in these cells. In regulatory T cells expanded by anti-CD3/CD28, A. princeps increased production of interleukin-10 and Foxp3.

Conclusions

The results suggest that A. princeps may be useful in the treatment of autoimmune diseases and organ transplantation rejection by inhibiting proliferation of inflammatory T cells, suppressing inflammatory processes in antigen-stimulated CD4+CD25- T cells and increasing activity of expanded regulatory T cells.

Anti-tumor effect of apicidin on Ishikawa human endometrial cancer cells both in vitro and in vivo by blocking histone deacetylase 3 and 4

Histone deacetylase (HDAC) inhibitors are a new class of anticancer agents that act by inhibiting cancer cell proliferation and inducing apoptosis both in vitro and in vivo. This study examined the anti-tumor effect of apicidin on human endometrial cancer Ishikawa cells in an animal model by inhibiting specific HDAC expression. Nude mice were injected subcutaneously (s.c.) with Ishikawa cells, and the levels of cell proliferation and apoptosis were measured in the tumor tissues after an apicidin treatment. The expression patterns of a specific HDAC class by apicidin were measured in Ishikawa endometrial cancer both in vitro and in vivo. The tumor volume and weight were measured after the apicidin treatment. Apicidin significantly increased the acetylated histone H3 levels in an Ishikawa cells in vitro culture but the levels of HDAC3 and HDAC4 expression were significantly decreased. Apicidin suppressed the tumor growth of transplanted Ishikawa cells, the expression of proliferative cell nuclear antigen (PCNA) and vascular endothelial growth factor (VEGF) in tumor xenograft model, respectively. The inhibitory effect of apicidin on tumor growth was mediated in part through the down-regulation of HDAC3 and HDAC4. We suggest that apicidin is an effective anti-tumor agent on human endometrial cancer cells, and acts by regulating cell proliferation and apoptosis through the down-regulation of HDAC3 and HDAC4.

Chrysanthemum morifolium Ramat (CM) extract protects human neuroblastoma SH-SY5Y cells against MPP+-induced cytotoxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Chrysanthemum morifolium Ramat (Asteraceae) has (CM) long been used in Korean and Chinese traditional herbal medicines with numerous therapeutic applications.

AIM OF THE STUDY

To evaluate the neuroprotective activities of Chrysanthemum morifolium (CM) extract against 1-methyl-4-phenylpridinium ions (MPP(+)), Parkinsonian toxin through oxidative stress and impaired energy metabolism, in human SH-SY5Y neuroblastoma cells and the underlying mechanisms.

MATERIALS AND METHODS

The effects of CM against MPP(+)-induced cytotoxicity and neuronal cell viability, oxidative damage, the expression of Bcl-2 and Bax, caspase-3 and poly(ADP-ribose) polymerase (PARP) proteolysis were evaluated by using SH-SY5Y neuroblastoma cells.

RESULTS

CM effectively inhibited the cytotoxicity and improved cell viability. CM also attenuated the elevation of reactive oxygen species (ROS) level, increase in Bax/Bcl-2 ratio, cleavage of caspase-3 and PARP proteolysis.

CONCLUSION

These results demonstrate that CM possesses potent neuroprotective activity and therefore, might be a potential candidate in neurodegenerative diseases such as Parkinson's disease.

Oral administration of curcumin suppresses production of matrix metalloproteinase (MMP)-1 and MMP-3 to ameliorate collagen-induced arthritis: inhibition of the PKCdelta/JNK/c-Jun pathway

We investigated whether oral administration of curcumin suppressed type II collagen-induced arthritis (CIA) in mice and its effect and mechanism on matrix metalloproteinase (MMP)-1 and MMP-3 production in CIA mice, RA fibroblast-like synoviocytes (FLS), and chondrocytes. CIA in mice was suppressed by oral administration of curcumin in a dose-dependent manner. Macroscopic observations were confirmed by histological examinations. Histological changes including infiltration of immune cells, synovial hyperplasia, cartilage destruction, and bone erosion in the hind paw sections were extensively suppressed by curcumin. The histological scores were consistent with clinical arthritis indexes. Production of MMP-1 and MMP-3 were inhibited by curcumin in CIA hind paw sections and tumor necrosis factor (TNF)-alpha-stimulated FLS and chondrocytes in a dose-dependent manner. As for the mechanism, curcumin inhibited activating phosphorylation of protein kinase Cdelta (PKCdelta) in CIA, FLS, and chondrocytes. Curcumin also suppressed the JNK and c-Jun activation in those cells. This study suggests that the suppression of MMP-1 and MMP-3 production by curcumin in CIA is mediated through the inhibition of PKCdelta and the JNK/c-Jun signaling pathway.

Anti-inflammatory effects of Artemisia princeps in antigen-stimulated T cells and regulatory T cells

OBJECTIVES

The aim was to investigate the anti-inflammatory effects of Artemisia princeps extract on the activity of anti-CD3/CD28-stimulated CD4(+)CD25(-) T cells and antigen-expanded regulatory T cells.

METHODS

CD4(+)CD25(-) T cells were activated with coated anti-CD3 and anti-CD28 and cultured in the presence or absence of various concentrations of A. princeps extract. The cultures were pulsed on Day 6 with [(3)H]thymidine and, after harvesting the cells, [(3)H]thymidine incorporation was measured. For analysis of interleukin-2 and interferon-gamma secreted from CD4(+)CD25(-) T cells, culture supernatants were collected on Days 2 and 6. For the analysis of interleukin-10 secreted from the CD4(+)CD25(-) T cells and expanded regulatory T cells, supernatants were collected after 2 and 7 days, respectively. Cytokine levels were determined using an enzyme-linked immunosorbent assay. Potential medicinal components of the A. princeps extract were determined using gas chromatography-mass spectrometry.

KEY FINDINGS

A. princeps (30 microg/ml) effectively suppressed proliferation of CD4(+)CD25(-) T cells that were stimulated with anti-CD3/CD28 without causing cytotoxicity in spleen cells incubated under conditions lacking antigen stimulation. A. princeps inhibited production of the pro-inflammatory cytokines interleukin-2 and interferon-gamma in anti-CD3/CD28-stimulated CD4(+)CD25(-) T cells. Also, the extract slightly increased production of the anti-inflammatory cytokine interleukin-10 in these cells. In regulatory T cells expanded by anti-CD3/CD28, A. princeps increased production of interleukin-10 and Foxp3.

CONCLUSIONS

The results suggest that A. princeps may be useful in the treatment of autoimmune diseases and organ transplantation rejection by inhibiting proliferation of inflammatory T cells, suppressing inflammatory processes in antigen-stimulated CD4(+)CD25(-) T cells and increasing activity of expanded regulatory T cells.

Rapamycin down-regulates inducible nitric oxide synthase by inducing proteasomal degradation

We investigated the effect of rapamycin, a specific inhibitor of the mammalian serine/threonine kinase, mammalian target of rapamycin (mTOR), on the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Pretreatment of cells with rapamycin significantly inhibited LPS-induced nitrite production and the expression of iNOS protein in a dose-dependent manner. However, LPS-induced mRNA expression of iNOS and its concomitant activation of nuclear factor (NF)-kappaB remained unchanged by rapamycin. Intriguingly, LPS-induced nitrite production and iNOS protein expression were partially blocked at nanomolar concentrations of rapamycin, whereas phosphorylation of both p70 S6 kinase and 4E-BP1 was completely abolished. The suppression of LPS-induced iNOS expression by rapamycin was reversed by the protease inhibitor lactacystin. Furthermore, rapamycin treatment stimulated 20S proteasome activity, which was slightly elevated by LPS. Taken together, our findings strongly suggest that rapamycin down-regulates LPS-induced iNOS protein expression via proteasomal activation, as well as through inhibition of the mTOR signaling pathway.

Inhibitory effect of saponin fraction from Codonopsis lanceolata on immune cell-mediated inflammatory responses

Saponin components are known to be pharmaceutically, cosmetically and nutraceutically valuable principles found in various herbal medicine. In this study, we evaluated the inhibitory role of saponin fraction (SF), prepared from C. lanceolata, an ethnopharmacologically famous plant, on various inflammatory responses managed by monocytes, macrophages, lymphocytes and mast cells. SF clearly suppressed the release of nitric oxide (NO) and tumor necrosis factor (TNF)-alpha, but not prostaglandin E(2) (PGE(2)). While this fraction did not scavenge the reactivity of SNP-induced radicals in RAW264. 7 cells, it negatively modulated the phagocytic uptake of macrophages treated with FITC-dextran. Interestingly, SF completely diminished cell-cell adhesion events induced by both CD29 and CD43, but not cell-fibronectin adhesion. Concanavalin (Con) A [as well phytohemaglutinin A (PHA)]-induced proliferation of splenic lymphocytes as well as interferon (IFN)-gamma production were also clearly suppressed by SF treatment. Finally, SF also significantly blocked the degranulation process of mast cell line RBL-2H3 cell as assessed by DNP-BSA-induced beta-hexosaminidase activity. The anti-inflammatory activities of SF on NO production seemed to be due to inhibition of nuclear factor (NF)-kappaB activation signaling, since it blocked the phosphorylation of inhibitor of kappaB (IkappaB)alpha as well as inducible NO synthase (iNOS) expression. Therefore, these results suggest that SF may be considered as a promising herbal medicine with potent anti-inflammatory actions.

Evidence for HTR1A and LHPP as interacting genetic risk factors in major depression

The HTR1A -1019C>G genotype was associated with major depression in the Utah population. Linkage analysis on Utah pedigrees with strong family histories of major depression including only cases with the HTR1A -1019G allele revealed a linkage peak on chromosome 10 (maximum HLOD=4.4). Sequencing of all known genes in the linkage region revealed disease-segregating single-nucleotide polymorphisms (SNPs) in LHPP. LHPP SNPs were also associated with major depression in both Utah and Ashkenazi populations. Consistent with the linkage evidence, LHPP associations depended on HTR1A genotype. Lhpp or a product of a collinear brain-specific transcript, therefore, may interact with Htr1a in the pathogenesis of major depression.

Cordycepin attenuates neointimal formation by inhibiting reactive oxygen species-mediated responses in vascular smooth muscle cells in rats

We determined the action mechanism of cordycepin, a major bioactive component of Cordyceps militaris, on responses of rat aortic smooth muscle cells (RASMCs) and on vascular disorders, especially neointimal formation. Cordycepin inhibited platelet-derived growth factor-BB (PDGF-BB)-induced RASMCs migration and proliferation in a dose-dependent manner. However, pre-treatment with N(omega)-nitro-L-arginine methyl ester, a nitric oxide synthase (NOS) inhibitor, and 1,3-dipropyl-8-sulphophenylxanthine (DPSPX), an A(1)/A(2) adenosine-receptor antagonist, abolished the inhibitory role of cordycepin. Cordycepin suppressed the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) and heat shock protein 27 (Hsp27), but not that of extracellular signal-regulated kinase (ERK) 1/2 in RASMCs stimulated by PDGF-BB. The production of reactive oxygen species (ROS), O(2)(-) and H(2)O(2), induced by PDGF-BB was abolished by the treatment of cordycepin. Moreover, the sprout outgrowth of aortic rings by PDGF-BB was inhibited by cordycepin. In vivo neointimal formation evoked by balloon-injury was significantly attenuated by the administration of cordycepin. These results demonstrate that cordycepin may exert inhibitory effects on PDGF-BB-induced migration and proliferation via interfering with adenosine receptor-mediated NOS pathways, thus resulting in the attenuation of neointima formation. In conclusion, cordycepin may be a potent, promising anti-atherosclerosis agent.

Tumor necrosis factor alpha-induced interleukin-32 is positively regulated via the Syk/protein kinase Cdelta/JNK pathway in rheumatoid synovial fibroblasts

OBJECTIVE

Interleukin-32 (IL-32) is a recently discovered cytokine that appears to play a critical role in human rheumatoid arthritis (RA). It is highly expressed in synovium and fibroblast-like synoviocytes (FLS) from RA patients, but not in patients with osteoarthritis (OA). This study was undertaken to assess IL-32 levels in RA synovial fluid (SF) and to investigate the secretion and regulation of IL-32 in RA FLS.

METHODS

FLS and SF were obtained from the joints of RA patients. The secretion and expression of IL-32 and activation of signaling molecules were examined by enzyme-linked immunosorbent assay, immunoblotting, immunoprecipitation, reverse transcriptase-polymerase chain reaction, and small interfering RNA (siRNA) transfection.

RESULTS

IL-32 levels were high in RA SF compared with OA SF. Furthermore, RA FLS expressed and secreted IL-32 when stimulated with tumor necrosis factor alpha (TNFalpha). TNFalpha-induced expression of IL-32 was significantly suppressed, in a dose-dependent manner, by inhibitors of Syk, protein kinase Cdelta (PKCdelta), and JNK and by knockdown of these kinases and c-Jun with siRNA. We also observed that PKCdelta mediated the activation of JNK and c-Jun, and experiments using specific inhibitors and siRNA demonstrated that Syk was the upstream kinase for the activation of PKCdelta.

CONCLUSION

The present findings suggest that IL-32 may be a newly identified prognostic biomarker in RA, thereby adding valuable knowledge to the understanding of this disease. The results also demonstrate that the production of IL-32 in RA FLS is regulated by Syk/PKCdelta-mediated signaling events.

Lysophosphatidic acid receptor 2 and Gi/Src pathway mediate cell motility through cyclooxygenase 2 expression in CAOV-3 ovarian cancer cells

Lysophosphatidic acid (LPA) is a bioactive phospholipids and involves in various cellular events, including tumor cell migration. In the present study, we investigated LPA receptor and its transactivation to EGFR for cyclooxygenase-2 (COX-2) expression and cell migration in CAOV-3 ovarian cancer cells. LPA induced COX-2 expression in a dose-dependent manner, and pretreatment of the cells with pharmacological inhibitors of Gi (pertussis toxin), Src (PP2), EGF receptor (EGFR) (AG1478), ERK (PD98059) significantly inhibited LPA- induced COX-2 expression. Consistent to these results, transfection of the cells with selective Src siRNA attenuated COX-2 expression by LPA. LPA stimulated CAOV-3 cell migration that was abrogated by pharmacological inhibitors and antibody of EP2. Higher expression of LPA2 mRNA was observed in CAOV-3 cells, and transfection of the cells with a selective LPA2 siRNA significantly inhibited LPA-induced activation of EGFR and ERK, as well as COX-2 expression. Importantly, LPA2 siRNA also blocked LPA-induced ovarian cancer cell migration. Collectively, our results clearly show the significance of LPA2 and Gi/Src pathway for LPA-induced COX-2 expression and cell migration that could be a promising drug target for ovarian cancer cell metastasis.

Immunoglobulin and cytokine production from mesenteric lymph node lymphocytes is regulated by extracts of Cordyceps sinensis in C57Bl/6N mice

Cordyceps sinensis, one of the well-known fungi used in traditional Chinese medicine, is recognized to play a role in the metabolic process of inflammation and immunity. The purpose of this study was to evaluate the effects of water extracts of C. sinensis on the immune function of mesenteric lymph node (MLN) lymphocytes in C57Bl/6N mice. C. sinensis-treated mice were administered the respective extract by oral gavage for 4 weeks. Immunoglobulin E concentrations in serum and MLN lymphocytes were significantly lower in C. sinensis-treated mice than in control mice. In contrast, the immunoglobulin A concentration from the C. sinensis group was higher than that in control mice. C. sinensis increased the proportion of CD4(+) and CD8(+) T cells in MLN lymphocytes. C. sinensis significantly decreased interleukin-4 and interleukin-10 cytokine concentrations. Therefore, water extracts of C. sinensis modulate immune parameters through regulation of immunoglobulin production resulting from decreased T-lymphocyte helper 2 cytokine secretion and reduce cytokine secretion in MLN lymphocytes.

Gene Transfer of Redox Factor-1 Inhibits Neointimal Formation

The role of apurinic/apyrimidinic endonuclease-1/redox factor-1 (Ref-1) in vascular smooth muscle cells has yet to be clearly elucidated. Therefore, we attempted to determine the roles of Ref-1 in the migration induced by platelet-derived growth factor (PDGF)-BB and in its signaling in rat aortic smooth muscle cells (RASMCs). Cellular migration, superoxide (O 2 −· ) production, Rac-1 activity, and neointima formation were determined in cells transfected with adenoviruses encoding for Ref-1 (AdRef-1) and small interference RNA of Ref-1. Overexpression of Ref-1 induced by treatment with RASMCs coupled with AdRef-1 inhibited the migration induced by PDGF-BB. PDGF-BB also increased the phosphorylation of the PDGFβ receptor, spleen tyrosine kinase (Syk), mitogen-activated protein kinase, and heat shock protein 27, but these increases were significantly inhibited by AdRef-1 treatment. PDGF-BB increased O 2 −· production and Rac-1 activity, and these were diminished in cells transfected with AdRef-1. In contrast, RASMC migration, phosphorylation of Syk and O 2 −· production in response to PDGF-BB were increased by the knock down of Ref-1 with small interference RNA. The phosphorylation of PDGFβ receptor in response to PDGF-BB was inhibited completely by the Syk inhibitor and was partly attenuated by a NADPH oxidase inhibitor. PDGF-BB increased the sprout outgrowth of the aortic ring ex vivo, which was inhibited in the AdRef-1–infected RASMCs as compared with the controls. Balloon injury–induced neointimal formation was significantly attenuated by the gene transfer of AdRef-1. These results indicate that Ref-1 inhibits the PDGF-mediated migration signal via the inhibition of reactive oxygen species–mediated Syk activity in RASMCs.

Cofilin phosphorylation mediates proliferation in response to platelet-derived growth factor-BB in rat aortic smooth muscle cells

Cofilin, an actin-binding protein, is essential for a variety of cell responses. In this study, we investigated the correlation between proliferation and cofilin phosphorylation in response to platelet-derived growth factor (PDGF) in rat aortic smooth muscle cells (RASMCs). The phosphorylation of cofilin and activity of mitogen-activated protein kinase (MAPK) were measured by Western analyses and proliferation in RASMCs was measured by BrdU incorporation assays. The phosphorylation of cofilin in RASMCs was decreased by PDGF-BB treatment at 10 min, but recovered to the level of the quiescent state at 60 min. PDGF-BB-induced dephosphorylation of cofilin was inhibited by pretreatment with piceatannol (a spleen tyrosine kinase [Syk] inhibitor), PP2 (a Src inhibitor), or SP600125 (a c-Jun N-terminal kinase [JNK] inhibitor), but not by PD98059, an inhibitor of extracellular signal-regulated kinase 1/2. PDGF-BB increased JNK activity and proliferation, and these responses were suppressed by kinase inhibitors and small interference RNA-cofilin. The results suggest that PDGF-BB-induced dephosphorylation of cofilin can be promoted via the JNK pathway, which is regulated by both Syk and Src kinases and that cofilin dephosphorylation may be involved in PDGF-BB-induced RASMC proliferation.

Dimensionality-controlled insulator-metal transition and correlated metallic state in 5d transition metal oxides Sr n+1Ir nO3n+1 (n=1, 2, and infinity)

We investigated the electronic structures of the 5d Ruddlesden-Popper series Sr n+1Ir nO3n+1 (n=1, 2, and infinity) using optical spectroscopy and first-principles calculations. As 5d orbitals are spatially more extended than 3d or 4d orbitals, it has been widely accepted that correlation effects are minimal in 5d compounds. However, we observed a Mott insulator-metal transition with a change of bandwidth as we increased n. In addition, the artificially synthesized perovskite SrIrO3 showed a very large mass enhancement of about 6, indicating that it was in a correlated metallic state.

Reversine increases the plasticity of lineage-committed cells toward neuroectodermal lineage

Functional dedifferentiation of lineage-committed cells toward pluripotency may have a great potential in regenerative medicine. Reversine has been shown to induce dedifferentiation of multiple terminally differentiated mesodermal origin cells, which are capable of being directed to differentiate into other cell types within mesodermal lineages. However, the possibilities of these cells to give rise to other lineages have not been examined. Here we show that large scale gene expression profiling of reversine-treated C2C12 myoblasts identifies a subset of up-regulated genes involved in specification of neuroectodermal as well as mesodermal lineages. Reversine treatment leads to up-regulation of priming genes of neuroectodermal lineages, such as Ngn2, Nts, Irx3, Pax7, Hes1, and Hes6, through active histone modifications in the promoter regions of these genes. Additionally, reversine increases the expression of markers for other cell types of mesodermal lineages, Ogn and apoE, via inducing active histone modifications, while down-regulating the myogenic basic helix-loop-helix factor, MyoD, via repressive histone modifications. Consistent with up-regulation of these genes, reversine-treated C2C12 myoblasts redifferentiate into neural as well as mesodermal lineages, under appropriate stimuli. Taken together, these results indicate that reversine induces a multipotency of C2C12 myoblasts via inducing a specific combination of active histone modifications. Collectively, our findings provide a mechanistic rationale for the application of reversine to dedifferentiation of somatic cells.

Effects of trichostatin A, a histone deacetylase inhibitor, on the regulation of apoptosis in H-ras-transformed breast epithelial cells

This study examined the mechanism for the anti-cancer effects of histone deacetylase (HDAC) inhibitor trichostatin A (TsA) in H-ras-transformed human breast epithelial (MCF10A-ras) cells. The effects of TsA on anti-cancer effects of MCF10A-ras cells were determined by measuring the level of cell cycle regulator expression and apoptotic cell death using Western blotting and flow cytometry analysis, respectively. TsA induced morphological changes, apoptotic cell death and modulation of the cell cycle regulatory proteins in the MCF10A-ras cells. TsA increased the levels of acetylated histone H3 and H4 in MCF10A-ras cells. In addition, TsA markedly down-regulated the expression of cyclin D1 and CDK4, up-regulated the expression of p21WAF1 and p53 and induced cell cycle arrest at the G1 phase in MCF10A-ras cells. The levels of hyperphosphorylation of the Rb protein were lower in MCF10A-ras cells after the TsA treatment. Furthermore, the up-regulation of p53 promoted Bax expression, which led to the activation of pro-caspase-3 and eventually to apoptosis in MCF10A-ras cells. TsA significantly increased the levels of ERK1/2 phosphorylation in MCF10A-ras cells. Overall, the TsA-activated ERK pathway plays an important role in cell cycle arrest and apoptosis through the ERK-dependent induction of p21 in Ras-related human cancer cells.

Thermal denaturation of the apo-cyclic AMP receptor protein and noncovalent interactions between its domains

Cyclic AMP receptor protein (CRP) is allosterically activated by cAMP and functions as a global transcription regulator in enteric bacteria. Structural information on CRP in the absence of cAMP (apo-CRP) is essential to fully understand its allosteric behavior. In this study we demonstrated interdomain interactions in apo-CRP, using a comparative thermodynamic approach to the intact protein and its isolated domains, which were prepared either by limited proteolysis or using recombinant DNA. Thermal denaturation of the intact apo-CRP, monitored by differential scanning calorimetry, revealed an apparently single cooperative transition with a slight asymmetry. Combined with circular dichroism and fluorescence analysis, the thermal denaturation of apo-CRP could be interpreted as a coupled process involving two individual transitions, each attributable to a structural domain. When isolated individually, both of the domains exhibited significantly altered thermal behavior, thus pointing to the existence of non-covalent interdomain interactions in the intact apo-CRP. These observations suggest that the allosteric conformational change of CRP upon binding to cAMP is achieved by perturbing or modifying pre-existing interdomain interactions. They also underline the effectiveness of a comparative approach using calorimetric and structural probes for studying the thermodynamics of a protein.

PKC delta in preeclamptic placentas promotes Bax dissociation from 14-3-3 zeta through 14-3-3 zeta phosphorylation

OBJECTIVE

We investigated placental apoptosis and the expression of and interactions between 14-3-3 and Bcl-2 family proteins during preeclampsia. In addition, we explored the mechanism of Bax dissociation from 14-3-3, hypothesizing that PKC-mediated phosphorylation of 14-3-3 results in dissociation of Bax from 14-3-3 proteins, and leads to apoptosis.

METHODS

Placental samples from 10 women with preeclampsia and 10 normotensive control patients were analyzed using M30-specific immunohistochemistry to assess placental apoptosis. Biochemical markers of cellular apoptosis, such as cleaved caspase-3, Bax, Bcl-2, 14-3-3, and PKC were followed by Western blotting. Interaction of 14-3-3 proteins with Bax and with PKC was assessed by immunoprecipitation.

RESULTS

M30-positive cells were widespread in the preeclamptic placentas. The levels of cleaved caspase-3, Bax, 14-3-3 zeta, phospho-(Ser)-14-3-3, and PKC delta were significantly higher in the preeclamptic placentas than in normal placentas. Preeclampsia was also associated with weaker interactions between 14-3-3 zeta and Bax and stronger interactions between 14-3-3 zeta and PKC delta.

CONCLUSION

Our results suggest that PKC delta in preeclamptic placentas promotes Bax dissociation from 14-3-3 zeta through the phosphorylation of 14-3-3 zeta. This finding may at least in part explain the apoptosis-inducing activity of PKC delta, revealing the important role of PKC delta in the development of apoptosis-related diseases such as preeclampsia.