Colla corii asini might upregulate ZNF471 and THOC5 by KRAB domain-containing zinc-finger protein pathway and THO complex subunit 5 pathway to improve anemia of pregnant women with ß-thalassemia.

Pregnant patients with ß-thalassemia are more likely to have progressive anemia which expose them to risk of adverse pregnancy outcomes, blood transfusion, and iron overload. Results from our previous study indicated that Colla corii asini (CCA, E'jiao), a natural ingredient of traditional Chinese medicine, could significantly increase hemoglobin level of pregnant women with ß- thalassemia, but the underlying molecular mechanism was unclear. Thus, we applied high-throughput transcriptome sequencing to study the transcriptomic change before and after the CCA treatment. Twenty eligible pregnant women were recruited and randomized to either the CCA treatment group or the blank control group in a 3:1 ratio. Patients in the treatment group orally received daily 15 g CCA powder for 4 weeks. We analyzed the therapeutic effect indexes and the transcriptomic change in subjects' peripheral blood before and after treatment. We found that ß CD 41-42(-TTCT)/ßA was the main genotype of the subjects. The regulatory impact of CCA treatment became more evident among the subjects of genotype ß CD 41-42(-TTCT)/ßA. Gene ontogenesis analysis revealed that the top five molecular functions of differentially expressed genes were involved in membrane functionality and cellular structure. We further identified two consistent upregulated genes ZNF471 and THOC5 in the effective treatment group, which were engaged in Kruppel-associated box (KRAB) domain-containing zinc-finger protein pathway and THOC5 pathway, respectively. Based on our current findings, we hypothesize that the anti-anemia effect of CCA on pregnant women with ß-thalassemia might be related to translation regulation of spectrin synthesis, membrane stability, and eventually prolonged the life span of erythrocytes.

Inhibition of GLI2 with antisense-oligonucleotides: A potential therapy for the treatment of bladder cancer.

The sonic hedgehog (SHH) signaling pathway plays an integral role in the maintenance and progression of bladder cancer (BCa) and SHH inhibition may be an efficacious strategy for BCa treatment. We assessed an in-house human BCa tissue microarray and found that the SHH transcription factors, GLI1 and GLI2, were increased in disease progression. A panel of BCa cell lines show that two invasive lines, UM-UC-3 and 253J-BV, both express these transcription factors but UM-UC-3 produces more SHH ligand and is less responsive in viability to pathway stimulation by recombinant human SHH or smoothened agonist, and less responsive to inhibitors including the smoothened inhibitors cyclopamine and SANT-1. In contrast, 253J-BV was highly responsive to these manipulations. We utilized a GLI1 and GLI2 antisense oligonucleotide (ASO) to bypass pathway mechanics and target the transcription factors directly. UM-UC-3 decreased in viability due to both ASOs but 253J-BV was only affected by GLI2 ASO. We utilized the murine intravesical orthotopic human BCa (mio-hBC) model for the establishment of noninvasive BCa and treated tumors with GLI2 ASO. Tumor size, growth rate, and GLI2 messenger RNA and protein expression were decreased. These results suggest that GLI2 ASO may be a promising new targeted therapy for BCa.

Differential Activation of NLRP3, AIM2, and IFI16 Inflammasomes in Humans with Acute and Chronic Hepatitis B.

Nod-like receptor protein 3 (NLRP3), absent in melanoma 2 (AIM2), and interferon gamma inducible protein 16 (IFI16) are innate immune sensors for intracellular microbes, which can be activated by various dangerous signals and subsequently lead to caspase-1 (CASP1) activation and the maturation cleavage of effector molecules pro-IL-1ß and pro-IL-18. Their roles in immunopathology of acute and chronic hepatitis B virus (HBV) infection are still unclear. In this study, we first investigated the activation of NLRP3, AIM2, and IFI16 inflammasomes in peripheral blood mononuclear cells (PBMCs) from patients infected with acute hepatitis B (AHB) and chronic hepatitis B (CHB) by quantitative real-time PCR and enzyme-linked immunosorbent assay. We next analyzed the impact of hepatitis B e antigen (HBeAg) on activation of AIM2 and IFI16 inflammasomes in PBMCs of CHB patients stimulated in vitro with AIM2 and IFI16 agonist ligands, poly (dA:dT) and VACA-70mer, respectively. The results showed that the mRNA expression levels of AIM2, IFI16, and CASP1 in PBMCs from AHB and CHB patients were both upregulated. Furthermore, the mRNA levels of AIM2 and IFI16 in CHB patients were significantly positively correlated with serum HBV loads. However, only in patients with AHB there was elevation of serum IL-1ß and IL-18. There was no activation of NLRP3, AIM2, and IFI16 inflammasomes in CHB patients. Stimulation of PBMCs of CHB patients in vitro with poly (dA:dT) and VACA-70mer induced the activation of AIM2 and IFI16 inflammasomes, respectively. This ligand-induced activation was suppressed by HBeAg. Our results suggest that there exists activation of the AIM2 and IFI16 inflammasomes, but not the NLRP3 inflammasome, in AHB, and the activation of the AIM2 and IFI16 inflammasomes can be inhibited by HBeAg in CHB, which may contribute to HBV-induced immunotolerance.

A novel fluorinated triazole derivative suppresses macrophage activation and alleviates experimental colitis via a Twist1-dependent pathway.

Hyperactivated macrophages play a key role in the initiation and perpetuation of mucosal inflammation in Crohn's disease (CD). Increasing evidence suggests that the basic helix-loop-helix (bHLH) repressor Twist1 can suppress activation of nuclear factor-κB (NF-κB) and the subsequent production of TNF-α, which are both essential elements of macrophage activation. Thus, developing novel therapeutic strategies to enhance Twist1 expression and to inhibit macrophage activation may be beneficial for CD treatment. In the present study, a series of trifluoroethyl thiazolo[3,2-b][1,2,4]triazole derivatives were used to investigate their potential anti-inflammatory activities and the underlying mechanism. In a biological activity screen, compound 7# (Thiazolo[3,2-b][1,2,4]triazole-5-methanamine, 6-phenyl-α-(trifluoromethyl)-, (αR)-, TT-TFM) suppressed the activation of macrophages. Consistent with the in vitro data, TT-TFM protected against 2,4,6-trinitrobenzene sulfonic acid (TNBS), dextran sulfate sodium (DSS)-induced acute colitis and IL-10 knockout (KO) chronic colitis, as judged by body weight changes and colonic pathological damage. A mechanistic study based on microarray analysis and gene interference experiments indicated that TT-TFM exerted anti-inflammatory effects by enhancing Twist1 expression and subsequently blocking the NF-κB/TNF-α pathway. In addition, pretreatment with lentiviruses encoding shRNA targeting Twist1 could abolish the therapeutic effect of TT-TFM in TNBS colitis. Ultimately, TT-TFM showed anti-colitis activity by reducing NF-κB activation and the TNF-α level by promoting Twist1 expression; thus, TT-TFM may offer a therapeutic strategy for CD patients.

Up-regulation of receptor interaction protein 140 promotes glucolipotoxicity-induced damage in MIN6 cells.

The receptor interaction protein 140 (RIP140) cofactor is a key regulator of metabolic balance, but its function in glucose- and lipid-mediated damage in islet ß cells is unknown and was investigated in this study. RIP140 expression and distribution was evaluated in MIN6 cells under high glucose and lipid conditions using real-time Polymerase Chain Reaction (PCR), western blotting and confocal laser scanning microscopy. Cells were separately treated with 500 µM palmitic acid and 25 mM glucose when RIP140 expression was upregulated or downregulated, and cell viability, apoptosis rate, the level of oxidative stress and insulin secretion was assessed, as was the expression of related genes. Increased glucose and palmitic acid elevated RIP140 expression and distribution in nuclei. Overexpression of RIP140 promoted apoptosis but inhibited cell viability in MIN6 cells, and basal insulin secretion and glucose-stimulated insulin secretion levels were altered following treatment with glucose and palmitic acid. In addition, oxidative stress was elevated, phosphorylated extracellular signal-regulated kinases 1/2 and uncoupling protein 2 messenger RNA (mRNA) abundance were increased, B-cell lymphoma-2 protein levels were decreased, and peroxisome proliferators activated receptor gamma co-activator 1 alpha, phosphoenolpyruvate carboxykinase , and pancreatic and duodenal homeobox-1 mRNA levels were downregulated. Furthermore, glucolipotoxicity-induced damage was reversed when RIP140 expression was downregulated by small interfering RNA (SiRNA). RIP140 promotes islet ß cells damage caused by glucolipotoxicity.

Microarray analysis reveals Tmub1 as a cell cycle-associated protein in rat hepatocytes.

Transmembrane and ubiquitin-like domain containing protein 1 (Tmub1), formerly known as hepatocyte odd protein shuttling (HOPS) has been recognized as a ubiquitously expressed shuttling protein that moves between the nucleus and cytoplasm in hepatocytes. Tmub1 is involved in liver regeneration and functions as a bridging protein in tumor cell proliferation. To investigate the transcriptional profile and potential biological processes affected by Tmub1 expression in normal rat hepatocytes, microarray and bioinformatics experiments were used to identify 127 mRNAs differentially expressed between Tmub1­overexpression, Tmub1­knockdown and normal BRL­3A cells (fold­change ≥2.5). The expression levels of 17 key node genes associated with the cell cycle were confirmed by reverse transcription-quantitative polymerase chain reaction analysis. Flow cytometry, 5­Ethynyl­20­deoxyuridine, Cell Counting Kit­8 and western blotting experiments revealed the effects on the cell cycle and the inhibition of proliferation in BRL­3A cells overexpressing Tmub1. Further co­immunoprecipitation assays demonstrated that Tmub1 interacts with cyclin A2 during the cell cycle and that the overexpression of Tmub1 may postpone cyclin A2 and cyclin B1 degradation in the M phase. The results of the present study indicated that Tmub1 functions as a cell proliferation inhibitor and cell cycle­associated protein.

Neuropeptide Y promotes adipogenic differentiation in primary cultured human adipose-derived stem cells.

Neuropeptide Y (NPY) is an important neurotransmitter in the control of energy metabolism. Several studies have shown that obesity is associated with increased levels of NPY in the hypothalamus. We hypothesized that the release of NPY has coordinated and integrated effects on energy metabolism in different tissues, such as adipocyte tissue, resulting in increased energy storage and decreased energy expenditure. Whether NPY has role in the molecular mechanism of human adipocyte tissue remains unclear. We established the model of human adipose derived stem cells (hADSCs) from human adipose tissue and differentiated it into adipocytes in the presence of NPY at different concentrations (10-15-10-6 mmol/L). We then assessed hADSCs proliferation and differentiation by quantifying lipid accumulation and examining the expression levels of related adipocyte markers after differentiation. Furthermore, the specific markers of white adipocyte tissue (WAT) in hADSCs were also analyzed. The results showed that low doses of NPY stimulated hADSCs proliferation (p < 0.05), while high doses of NPY inhibited hADSCs proliferation (p < 0.05). NPY significantly promoted lipid accumulation and increased the size of lipid droplets during human adipogenic differentiation; the levels of adipocyte markers PPAR-γ and C/EBPα were also increased. At the same time, NPY also increased the levels of WAT markers Cidec and RIP140 after adipocyte differentiation. The results suggested high dose NPY inhibits the proliferation of hADSCs while promotes adipocyte differentiation and increases the expression of WAT markers. This may be the reason why increased levels of NPY can lead to a rise in body weight.

Chronic high-sucrose diet increases fibroblast growth factor 21 production and energy expenditure in mice.

Excess carbohydrate intake causes obesity in humans. On the other hand, acute administration of fructose, glucose or sucrose in experimental animals has been shown to increase the plasma concentration of anti-obesity hormones such as glucagon-like peptide 1 (GLP-1) and Fibroblast growth factor 21 (FGF21), which contribute to reducing body weight. However, the secretion and action of GLP-1 and FGF21 in mice chronically fed a high-sucrose diet has not been investigated. To address the role of anti-obesity hormones in response to increased sucrose intake, we analyzed mice fed a high-sucrose diet, a high-starch diet or a normal diet for 15 weeks. Mice fed a high-sucrose diet showed resistance to body weight gain, in comparison with mice fed a high-starch diet or control diet, due to increased energy expenditure. Plasma FGF21 levels were highest among the three groups in mice fed a high-sucrose diet, whereas no significant difference in GLP-1 levels was observed. Expression levels of uncoupling protein 1 (UCP-1), FGF receptor 1c (FGFR1c) and ß-klotho (KLB) mRNA in brown adipose tissue were significantly increased in high sucrose-fed mice, suggesting increases in FGF21 sensitivity and energy expenditure. Expression of carbohydrate responsive element binding protein (ChREBP) mRNA in liver and brown adipose tissue was also increased in high sucrose-fed mice. These results indicate that FGF21 production in liver and brown adipose tissue is increased in high-sucrose diet and participates in resistance to weight gain.

Neuropilin-1 promotes Hedgehog signaling through a novel cytoplasmic motif.

Hedgehog (HH) signaling critically regulates embryonic and postnatal development as well as adult tissue homeostasis, and its perturbation can lead to developmental disorders, birth defects, and cancers. Neuropilins (NRPs), which have well-defined roles in Semaphorin and VEGF signaling, positively regulate HH pathway function, although their mechanism of action in HH signaling remains unclear. Here, using luciferase-based reporter assays, we provide evidence that NRP1 regulates HH signaling specifically at the level of GLI transcriptional activator function. Moreover, we show that NRP1 localization to the primary cilium, a key platform for HH signal transduction, does not correlate with HH signal promotion. Rather, a structure-function analysis suggests that the NRP1 cytoplasmic and transmembrane domains are necessary and sufficient to regulate HH pathway activity. Furthermore, we identify a previously uncharacterized, 12-amino acid region within the NRP1 cytoplasmic domain that mediates HH signal promotion. Overall, our results provide mechanistic insight into NRP1 function within and potentially beyond the HH signaling pathway. These insights have implications for the development of novel modulators of HH-driven developmental disorders and diseases.

Combined deletion and DNA methylation result in silencing of FAM107A gene in laryngeal tumors.

Larynx squamous cell carcinoma (LSCC) is characterized by complex genotypes, with numerous abnormalities in various genes. Despite the progress in diagnosis and treatment of this disease, 5-year survival rates remain unsatisfactory. Therefore, the extended studies are conducted, with the aim to find genes, potentially implicated in this cancer. In this study, we focus on the FAM107A (3p14.3) gene, since we found its significantly reduced expression in LSCC by microarray profiling (Affymetrix U133 Plus 2.0 array). By RT-PCR we have confirmed complete FAM107A downregulation in laryngeal cancer cell lines (15/15) and primary tumors (21/21) and this finding was further supported by FAM107A protein immunohistochemistry (15/15). We further demonstrate that a combined two hit mechanism including loss of 3p and hypermethylation of FAM107A promoter region (in 9/15 cell lines (p < 0.0001) and in 15/21 primary tumors (p < 0.0001)) prevails in the gene transcriptional loss. As a proof of principle, we show that Decitabine - a hypomethylating agent - restores FAM107A expression (5 to 6 fold increase) in the UT-SCC-29 cell line, characterized by high DNA methylation. Therefore, we report the recurrent inactivation of FAM107A in LSCC, what may suggest that the gene is a promising tumor suppressor candidate involved in LSCC development.

Carbon monoxide protects against hepatic steatosis in mice by inducing sestrin-2 via the PERK-eIF2α-ATF4 pathway.

Nonalcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome, has emerged as one of the most common causes of chronic liver disease in developed countries over the last decade. NAFLD comprises a spectrum of pathological hepatic changes, including steatosis, steatohepatitis, advanced fibrosis, and cirrhosis. Autophagy, a homeostatic process for protein and organelle turnover, is decreased in the liver during the development of NAFLD. Previously, we have shown that carbon monoxide (CO), a reaction product of heme oxygenase (HO) activity, can confer protection in NAFLD, though the molecular mechanisms remain unclear. We therefore investigated the mechanisms underlying the protective effect of CO on methionine/choline-deficient (MCD) diet-induced hepatic steatosis. We found that CO induced sestrin-2 (SESN2) expression through enhanced mitochondrial ROS production and protected against MCD-induced NAFLD progression through activation of autophagy. SESN2 expression was increased by CO or CO-releasing molecule (CORM2), in a manner dependent on signaling through the protein kinase R-like endoplasmic reticulum kinase (PERK), eukaryotic initiation factor-2 alpha (eIF2α)/ activating transcription factor-4 (ATF4)-dependent pathway. CO-induced SESN2 upregulation in hepatocytes contributed to autophagy induction through activation of 5'-AMP-activated protein kinase (AMPK) and inhibition of mechanistic target of rapamycin (mTOR) complex I (mTORC1). Furthermore, we demonstrate that CO significantly induced the expression of SESN2 and enhanced autophagy in the livers of MCD-fed mice or in MCD-media treated hepatocytes. Conversely, knockdown of SESN2 abrogated autophagy activation and mTOR inhibition in response to CO. We conclude that CO ameliorates hepatic steatosis through the autophagy pathway induced by SESN2 upregulation.

GADD45a Regulates Olaquindox-Induced DNA Damage and S-Phase Arrest in Human Hepatoma G2 Cells via JNK/p38 Pathways.

Olaquindox, a quinoxaline 1,4-dioxide derivative, is widely used as a feed additive in many countries. The potential genotoxicity of olaquindox, hence, is of concern. However, the proper mechanism of toxicity was unclear. The aim of the present study was to investigate the effect of growth arrest and DNA damage 45 alpha (GADD45a) on olaquindox-induced DNA damage and cell cycle arrest in HepG2 cells. The results showed that olaquindox could induce reactive oxygen species (ROS)-mediated DNA damage and S-phase arrest, where increases of GADD45a, cyclin A, Cdk 2, p21 and p53 protein expression, decrease of cyclin D1 and the activation of phosphorylation-c-Jun N-terminal kinases (p-JNK), phosphorylation-p38 (p-p38) and phosphorylation-extracellular signal-regulated kinases (p-ERK) were involved. However, GADD45a knockdown cells treated with olaquindox could significantly decrease cell viability, exacerbate DNA damage and increase S-phase arrest, associated with the marked activation of p-JNK, p-p38, but not p-ERK. Furthermore, SP600125 and SB203580 aggravated olaquindox-induced DNA damage and S-phase arrest, suppressed the expression of GADD45a. Taken together, these findings revealed that GADD45a played a protective role in olaquindox treatment and JNK/p38 pathways may partly contribute to GADD45a regulated olaquindox-induced DNA damage and S-phase arrest. Our findings increase the understanding on the molecular mechanisms of olaquindox.

A possible regulatory link between Twist 1 and PPARγ gene regulation in 3T3-L1 adipocytes.

BACKGROUND: Peroxisome proliferator-activated receptor γ (PPARγ) is a critical gene that regulates the function of adipocytes. Therefore, studies on the molecular regulation mechanism of PPARγ are important to understand the function of adipose tissue. Twist 1 is another important functional gene in adipose tissue, and hundreds of genes are regulated by Twist 1. The aim of this study was to investigate the regulation of Twist 1 and PPARγ expression in 3T3-L1 mature adipocytes. METHODS: We induced differentiation in 3T3-L1 preadipocytes and examined alterations in Twist 1 and PPARγ expression. We used the PPARγ agonist pioglitazone and the PPARγ antagonist T0070907 to investigate the effect of PPARγ on Twist 1 expression. In addition, we utilized retroviral interference and overexpression of Twist 1 to determine the effects of Twist 1 on PPARγ expression. RESULTS: The expression levels of Twist 1 and PPARγ were induced during differentiation in 3T3-L1 adipocytes. Application of either a PPARγ agonist (pioglitazone) or antagonist (T0070907) influenced Twist 1 expression, with up-regulation of Twist 1 under pioglitazone (1 µM, 24 h) and down-regulation of Twist 1 under T0070907 (100 µM, 24 h) exposure. Furthermore, the retroviral interference of Twist 1 decreased the protein and mRNA expression of PPARγ, while Twist 1 overexpression had the opposite effect. CONCLUSIONS: There was a possible regulatory link between Twist 1 and PPARγ in 3T3-L1 mature adipocytes. This regulatory link enhanced the regulation of PPARγ and may be a functional mechanism of Twist 1 regulation of adipocyte physiology and pathology.

Shikonin causes apoptosis by up-regulating p73 and down-regulating ICBP90 in human cancer cells.

Shikonin, a natural naphthoquinone isolated from the Chinese traditional medicine Zi Cao (purple gromwell), is known to suppress the growth of several cancer cell types. In this study, we evaluated the pro-apoptotic effects of shikonin on MCF-7 and HeLa cells, and investigated the underlying mechanism. Shikonin-induced apoptosis was associated with activation of caspase-3, poly(ADP-ribose) polymerase (PARP) cleavage, up-regulation of p73, and down-regulation of BCL-2. Shikonin also induced up-regulation of the tumor suppressor gene, p16(INK4A). Increasing transcriptional activity of p16(INK4A) by shikonin treatment, we observed in luciferase promoter assay, reflects reduced promoter binding by down-regulation of ICBP90 (inverted CCAAT box binding protein, 90 kDa), which are involved in down-regulation of its partner, DNMT1 (DNA methyltransferase 1). On the basis of these results, we conclude that shikonin causes apoptosis via a p73-related, caspase-3-dependent pathway.

ANKRD1 modulates inflammatory responses in C2C12 myoblasts through feedback inhibition of NF-κB signaling activity.

Transcription factors of the nuclear factor-kappa B (NF-κB) family play a pivotal role in inflammation, immunity and cell survival responses. Recent studies revealed that NF-κB also regulates the processes of muscle atrophy. NF-κB activity is regulated by various factors, including ankyrin repeat domain 2 (AnkrD2), which belongs to the muscle ankyrin repeat protein family. Another member of this family, AnkrD1 is also a transcriptional effector. The expression levels of AnkrD1 are highly upregulated in denervated skeletal muscle, suggesting an involvement of AnkrD1 in NF-κB mediated cellular responses to paralysis. However, the molecular mechanism underlying the interactive role of AnkrD1 in NF-κB mediated cellular responses is not well understood. In the current study, we examined the effect of AnkrD1 on NF-κB activity and determined the interactions between AnkrD1 expression and NF-κB signaling induced by TNFα in differentiating C2C12 myoblasts. TNFα upregulated AnkrD1 mRNA and protein levels. AnkrD1-siRNA significantly increased TNFα-induced transcriptional activation of NF-κB, whereas overexpression of AnkrD1 inhibited TNFα-induced NF-κB activity. Co-immunoprecipitation studies demonstrated that AnkrD1 was able to bind p50 subunit of NF-κB and vice versa. Finally, CHIP assays revealed that AnkrD1 bound chromatin at a NF-κB binding site in the AnrkD2 promoter and required NF-κB to do so. These results provide evidence of signaling integration between AnkrD1 and NF-κB pathways, and suggest a novel anti-inflammatory role of AnkrD1 through feedback inhibition of NF-κB transcriptional activity by which AnkrD1 modulates the balance between physiological and pathological inflammatory responses in skeletal muscle.

Dickkopf Homolog 3 Induces Stem Cell Differentiation into Smooth Muscle Lineage via ATF6 Signalling.

Smooth muscle cells (SMCs) are a key component of healthy and tissue engineered vessels and play a crucial role in vascular development and the pathogenic events of vascular remodeling i.e. restenosis. However, the cell source from which they can be isolated is limited. Embryonic stem (ES) cells that have the remarkable capability to differentiate into vascular SMCs in response to specific stimuli provide a useful model for studying SMC differentiation. Previous studies suggested that dickkopf homolog 3 (DKK3) has a role in human partially induced pluripotent stem cell to SMC differentiation. Here, we demonstrate that the expression of DKK3 is essential for the expression of SMC markers and myocardin at both the mRNA and protein levels during mouse ES cell differentiation into SMCs (ESC-SMC differentiation). Overexpression of DKK3 leads to further up-regulation of the aforementioned markers. Further investigation indicates that DKK3 added as a cytokine activates activating transcription factor 6 (ATF6), leading to the increased binding of ATF6 on the myocardin promoter and increased its expression. In addition, inhibition of extracellular signal-regulated kinases 1/2 (ERK1/2) promotes the expression of ATF6 and leads to further increase of myocardin transcription. Our findings offer a novel mechanism by which DKK3 regulates ESC-SMC differentiation by activating ATF6 and promoting myocardin expression.

Notch inhibits chondrogenic differentiation of mesenchymal progenitor cells by targeting Twist1.

While Notch signaling plays a critical role in the regulation of cartilage formation, its downstream targets are unknown. To address this we performed gain and losses of function experiments and demonstrate that Notch inhibition of chondrogenesis acts via up-regulation of the transcription factor Twist1. Upon Notch activation, murine limb bud mesenchymal progenitor cells in micromass culture displayed an inhibition of chondrogenesis. Twist1 was found to be exclusively expressed in mesenchymal progenitor cells at the onset stage of chondrogenesis during Notch activation. Inhibition of Notch signaling in these cells significantly reduced protein expression of Twist1. Furthermore, the inhibition effect of NICD1 on MPC chondrogenesis was markedly reduced by knocking down of Twist1. Constitutively active Notch signaling significantly enhanced Twist1 promoter activity; whereas mutation studies indicated that a putative NICD/RBPjK binding element in the promoter region is required for the Notch-responsiveness of the Twist1 promoter. Finally, chromatin immunoprecipitation assays further confirmed that the Notch intracellular domain influences Twist1 by directly binding to the Twist1 promoter. These data provide a novel insight into understanding the molecular mechanisms behind Notch inhibition of the onset of chondrogenesis.

RANKL promotes migration and invasion of hepatocellular carcinoma cells via NF-κB-mediated epithelial-mesenchymal transition.

BACKGROUND: Metastasis accounts for the most deaths in patients with hepatocellular carcinoma (HCC). Receptor activator of nuclear factor kappa B ligand (RANKL) is associated with cancer metastasis, while its role in HCC remains largely unknown. METHODS: Immunohistochemistry was performed to determine the expression of RANK in HCC tissue (n = 398). Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to examine the expression of RANK, E-cadherin, N-cadherin, vimentin, Snail, Slug, Twist and MMPs in HCC cells. Wound healing and Transwell assays were used to evaluate cell migration and invasion ability. RESULTS: We found that expression of RANK, the receptor of RANKL, was significantly higher in HCC tumor tissues than in peritumor liver tissues (p<0.001). Constitutive expression of RANK was detected in HCC cell lines, which can be up-regulated when HCC cells were stimulated with RANKL. Notably, in vitro experiments showed that activation of RANKL-RANK axis significantly promoted migration and invasion ability of HCC cells. In addition, RANKL stimulation increased the expression levels of N-cadherin, Snail, and Twist, while decreased the expression of E-cadherin, with concomitant activation of NF-κB signaling pathway. Moreover, administration of the NF-κB inhibitor attenuated RANKL-induced migration, invasion and epithelial-mesenchymal transition of HCC cells. CONCLUSIONS: RANKL could potentiate migration and invasion ability of RANK-positive HCC cells through NF-κB pathway-mediated epithelial-mesenchymal transition, which means that RANKL-RANK axis could be a potential target for HCC therapy.

p53-Dependent apoptosis induced in human bronchial epithelial (16-HBE) cells by PM(2.5) sampled from air in Guangzhou, China.

Epidemiological studies have shown that air pollution particulate matter (PM) is associated with increased respiratory morbidity and mortality. However, the mechanisms are not fully understood. Oxidative stress-mediated apoptosis plays an important role in the occurrence of respiratory diseases. In this study, human bronchial epithelial (16-HBE) cells were exposed to different concentrations (16-128 µg/ml) of PM(2.5) for 24 h to investigate the apoptosis induced by PM(2.5). The results showed that PM(2.5) exposure significantly induced apoptosis, DNA strand breaks, and oxidative damage in a dose-dependent manner in 16-HBE cells. The expression of p53 and p73 increased significantly along with the dose of PM(2.5) in 16-HBE cells, whereas the expression of p21(Cip1/WAF1) decreased; the expression of mdm2 increased and then decreased, but not significantly. Taken together, these observations indicate that PM(2.5) may lead to oxidative damage and induce apoptosis through the p53-dependent pathway in 16-HBE cells. p53-Dependent apoptosis mediated by DNA strand breaks may be an important mechanism of PM(2.5)-induced apoptosis in 16-HBE cells.

Changes in vitamin D target gene expression in adipose tissue monitor the vitamin D response of human individuals.

SCOPE: Vitamin D3, its biologically most active metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), and the vitamin D receptor (VDR) are important for adipose tissue biology. METHODS AND RESULTS: We extrapolated genomic VDR association loci in adipocytes from 55 conserved genome-wide VDR-binding sites in nonfat tissues. Taking the genes DUSP10, TRAK1, NRIP1, and THBD as examples, we confirmed the predicted VDR binding sites upstream of their transcription start sites and showed rapid mRNA up-regulation of all four genes in SGBS human pre-adipocytes. Using adipose tissue biopsy samples from 47 participants of a 5-month vitamin D3 intervention study, we demonstrated that all four primary VDR target genes can serve as biomarkers for the vitamin D3 responsiveness of human individuals. Changes in DUSP10 gene expression appear to be the most comprehensive marker, while THBD mRNA changes characterized a rather different group of study participants. CONCLUSION: We present a new approach to predict vitamin D target genes based on conserved genomic VDR-binding sites. Using human adipocytes as examples, we show that such ubiquitous VDR target genes can be used as markers for the individual's response to a supplementation with vitamin D3.