👤 Li-Yun Pang

IL-27, a heterodimeric cytokine of the IL-12 family, has diverse influences on the development of multiple inflammatory diseases. In this study, we identified the protective role of IL-27/IL-27R in host defense against Show less

Recent studies have demonstrated that commercially available lipid-lowering drugs cause various side effects; therefore, searching for anti-hyperlipidaemic compounds with lower toxicity is a research hotspot. This study was designed to investigate whether the marine-derived compound, 5-hydroxy-3-methoxy-5-methyl-4-butylfuran-2(5H)-one, has an anti-hyperlipidaemic activity, and the potential underlying mechanism in vitro. Results showed that the furanone had weaker cytotoxicity compared to positive control drugs. In RAW 264.7 cells, the furanone significantly lowered ox-LDL-induced lipid accumulation (~50%), and its triglyceride (TG)-lowering effect was greater than that of liver X receptor (LXR) agonist T0901317. In addition, it significantly elevated the protein levels of peroxisome proliferator-activated receptors (PPARα) and ATP-binding cassette (ABC) transporters, which could be partially inhibited by LXR antagonists, GSK2033 and SR9243. In HepG2 cells, it significantly decreased oleic acid-induced lipid accumulation, enhanced the protein levels of low-density lipoprotein receptor (LDLR), ABCG5, ABCG8 and PPARα, and reduced the expression of sterol regulatory element-binding protein 2 (~32%). PPARα antagonists, GW6471 and MK886, could significantly inhibit the furanone-induced lipid-lowering effect. Furthermore, the furanone showed a significantly lower activity on the activation of the expression of lipogenic genes compared to T0901317. Taken together, the furanone exhibited a weak cytotoxicity but had powerful TC- and TG-lowering effects most likely through targeting LXRα and PPARα, respectively. These findings indicate that the furanone has a potential application for the treatment of dyslipidaemia. Show less

Over two decades of research on cancer-associated epithelial-mesenchymal transition (EMT) led us to ascertain the occurrence of transitional intermediate states (collectively referred to as the EMT spectrum). Among the molecular factors that drive EMT, SNAI1 plays an indispensable role in regulating other core transcription factors, and this regulation is highly context-dependent. However, molecular investigation on this context-dependent regulation is still lacking. Using two ovarian cancer cell lines, we show that SNAI1 regulation on other core EMT-TFs switches from a repressive control in highly epithelial cells to an activation signaling in intermediate epithelial cells. Upon further scrutiny, we identify that the expression of early epithelial genes Show less

EIF4E is the rate-limiting factor in the mRNA translation of specific set of oncogenes. Snail is the core transcription factor of epithelial-mesenchymal transition (EMT), a key step of cancer metastasis. The connection between the two oncoproteins has not been well established in the human cancer tissues and in nasopharyngeal carcinoma (NPC). Here we showed that the positive correlative over-expression was seen between eIF4E and Snail in NPC tissues, and the expression was significantly higher in the metastatic NPC than in the un-metastatic NPC. In NPC cells, eIF4E knockdown significantly reduced Snail mRNA and protein levels, increased the mRNA level of E-cad (a direct downstream gene of Snail and a negative EMT marker), attenuated the invasive ability of the cells, and sensitized the cells to cisplatin in invasion. In contrast, enforced the expression of eIF4E significantly increased Snail mRNA and protein levels, and promoted the invasive ability in NPC cells. Under the condition of the high eIF4E expression, Snail knockdown significantly increased E-cad mRNA level and weaken the invasive ability of NPC cells. Finally, eIF4E directly bound Snail mRNA for translation initiation displayed by the RIP assay. Therefore, the results firstly suggested that eIF4E enhanced the Snail expression in both transcription and translation manner in human cancer tissues and targeting the eIF4E/Snail axis might intervene with the EMT and metastasis of NPC. This finding provided a new clue for further understanding the metastatic mechanism of human cancers and for preventing and treating NPC metastasis. Show less

Neovascular age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) are sight-threatening maculopathies with both environmental and genetic risk factors. We have previously shown relative risks posed by genes of the complement pathways to neovascular AMD and PCV. In this study, we investigated the haplotype-tagging single nucleotide polymorphisms (SNPs) in the The results revealed none of the six tagging SNPs of the This study showed no statistical significance in the genetic association of Show less

Since metabolic process differs between humans and mice, studies were performed in hamsters, which are generally considered to be a more appropriate animal model for studies of obesity-related metabolic disorders. The modulation of gut microbiota, bile acids and the farnesoid X receptor (FXR) axis is correlated with obesity-induced insulin resistance and hepatic steatosis in mice. However, the interactions among the gut microbiota, bile acids and FXR in metabolic disorders remained largely unexplored in hamsters. In the current study, hamsters fed a 60% high-fat diet (HFD) were administered vehicle or an antibiotic cocktail by gavage twice a week for four weeks. Antibiotic treatment alleviated HFD-induced glucose intolerance, hepatic steatosis and inflammation accompanied with decreased hepatic lipogenesis and elevated thermogenesis in subcutaneous white adipose tissue (sWAT). In the livers of antibiotic-treated hamsters, cytochrome P450 family 7 subfamily B member 1 (CYP7B1) in the alternative bile acid synthesis pathway was upregulated, contributing to a more hydrophilic bile acid profile with increased tauro- Show less

Evidence has demonstrated that the microRNA (miR) may play a significant role in the development of congenital heart disease (CHD). Here, we explore the mechanism of microRNA-592 (miR-592) in heart development and CHD with the involvement of KCTD10 and Notch signaling pathway in a CHD mouse model. Cardiac tissues were extracted from CHD and normal mice. Immunohistochemistry staining was performed to detect positive expression rate of KCTD10. A series of inhibitor, activators, and siRNAs was introduced to verified regulatory functions for miR-592 governing KCTD10 in CHD. Furthermore, the effect of miR-592 on cell proliferation and apoptosis was also investigated. Downregulated positive rate of KCTD10 was observed in CHD mice. Downregulation of miR-592 would upregulate expression of KCTD10 and inhibit the activation of Notch signaling pathway, thus promote cell proliferation. This study demonstrates that downregulation of miR-592 prevents CHD and hypoplastic heart by inhibition of the Notch signaling pathway via negatively binding to KCTD10. Show less

Podocytes are terminally differentiated cells with little proliferative capacity. The high expression levels of cell cycle inhibitory proteins, including p21, p27, and p57, play an important role in maintaining the low level of proliferation of mature podocytes. In the present study, we aimed to explore the role of yes-associated protein (YAP) signalling in adriamycin-induced podocyte re-entry into the cell cycle and dedifferentiation. Proliferating cell nuclear antigen (PCNA)-, cyclin-dependent kinase 4 (CDK4)-, and Cyclin D1-positive podocytes were found in mice with adriamycin-induced nephropathy. In vitro, adriamycin administration increased the percentage of cells in S phase and the upregulation of mesenchymal-related marker proteins. CDK4 and cyclin D1 were significantly up-regulated after incubation with adriamycin. Overexpression of YAP in podocytes promoted their entry into the cell cycle; up-regulated cyclin D1, desmin, and snail2 expression and down-regulated Wilms' tumour 1 (WT1) and nephrin production. Recombinant murine FGF-basic induced podocytes to re-enter the cell cycle, inhibited WT1 and nephrin, and increased desmin and snail2 expression. Pretreating podocytes with verteporfin, an inhibitor of YAP/ TEA domain transcription factor (TEAD), decreased the adriamycin-induced overexpression of cyclin D1 and reduced the ratio of S-phase podocytes. This result was further verified by knocking down YAP expression using RNA interference. In conclusion, adriamycin induced podocytes to re-enter the cell cycle via upregulation of CDK4 and cyclin D1 expression, which was at least partly mediated by YAP signalling. Re-entry into the cell cycle induced the over-expression of mesenchymal markers in podocytes. Show less

Circular RNAs (circRNAs) comprise a class of noncoding RNA molecules that play an important role in several normal cellular functions, as well as tumorigenesis in humans. However, the expression patterns and biological functions of circRNAs in ovarian cancer (OC) remain unclear. Therefore, we investigated the expression profiles and biological functions of certain circRNAs in OC tumor tissues. The expression of three circRNAs (VPS13C-has-circ-001567, RAD50-has-circ-00718, and SPECC1-has-circ-000013) was detected by real-time polymerase chain reaction in OC cell lines, and also in tumor and pericarcinous tissues obtained from 20 patients with OC. The function of VPS13C-has-circ-001567 in SKOV3 and OV-1063 cells was investigated by knockdown of VPS13C-has-circ-001567 and then analyzing any resultant effects on the cell cycle, cell proliferation, apoptosis, and cell invasion ability. E-cadherin and N-cadherin expressions were analyzed by immunofluorescence and western blotting. Finally, the tumorigenicity of OC cells was assessed in nude mice. The results showed that VPS13C-has-circ-001567 was expressed at significantly higher levels in OC tumor tissues compared with pericarcinous tissues, and this overexpression was associated with tumor node metastasis stage and lymph node metastasis. We found that knockdown of VPS13C-has-circ-001567 significantly promoted apoptosis and inhibited the proliferation of SKOV3 and OV-1063 cells in vitro. Knockdown of VPS13C-has-circ-001567 led to cell cycle arrest at G1 phase and decreased the percentage of S1 phase cells. Additionally, knockdown of VPS13C-has-circ-001567 decreased the invasion ability of SKOV3 and OV-1063 cells, and also changed the levels of E-cadherin and N-cadherin expressions. Knockdown of VPS13C-has-circ-001567 significantly reduced the tumorigenicity of OC cells. Taken together, our results suggest that VPS13C-has-circ-001567 plays a role in the development of OC and might be a prognostic marker and therapeutic target for OC. Show less

Polypoidal choroidal vasculopathy (PCV), a subtype of age-related macular degeneration (AMD) more frequently seen in East Asians, has both common and distinct clinical manifestations with typical neovascular AMD (tAMD). We aim to examine the extent to which common genetic variants are shared between these two subtypes. We performed the meta-analysis of association in a total of 1062 PCV patients, 1157 tAMD patients and 5275 controls of East Asian descent from the Genetics of AMD in Asians Consortium at the 34 known AMD loci. A total of eight loci were significantly associated with PCV, including age-related maculopathy susceptibility 2 (ARMS2)-HtrA serine peptidase 1 (HTRA1), complement factor H (CFH), C2-CFB-SKIV2L, CETP, VEGFA, ADAMTS9-AS2 and TGFBR1 (P<5 × 10 Show less

Genome-wide association studies (GWAS) on Parkinson's disease (PD) have mostly been done in Europeans and Japanese. No study has been done in Han Chinese, which make up nearly a fifth of the world population. We conducted the first Han Chinese GWAS analysing a total of 22,729 subjects (5,125 PD cases and 17,604 controls) from Singapore, Hong Kong, Malaysia, Korea, mainland China and Taiwan. We performed imputation, merging and logistic regression analyses of 2,402,394 SNPs passing quality control filters in 779 PD cases, 13,227 controls, adjusted for the first three principal components. 90 SNPs with association P < 10-4 were validated in 9 additional sample collections and the results were combined using fixed-effects inverse-variance meta-analysis. We observed strong associations reaching genome-wide significance at SNCA, LRRK2 and MCCC1, confirming their important roles in both European and Asian PD. We also identified significant (P < 0.05) associations at 5 loci (DLG2, SIPA1L2, STK39, VPS13C and RIT2), and observed the same direction of associations at 9 other loci including BST1 and PARK16. Allelic heterogeneity was observed at LRRK2 while European risk SNPs at 6 other loci including MAPT and GBA-SYT11 were non-polymorphic or very rare in our cohort. Overall, we replicate associations at SNCA, LRRK2, MCCC1 and 14 other European PD loci but did not identify Asian-specific loci with large effects (OR > 1.45) on PD risk. Our results also demonstrate some differences in the genetic contribution to PD between Europeans and Asians. Further pan-ethnic meta-analysis with European GWAS cohorts may unravel new PD loci. Show less

Vascular smooth muscle cell proliferation, migration, and dedifferentiation are critical for vascular diseases. Recently, it was demonstrated that Notch receptors have opposing effects on intima formation after vessel injury. Therefore, it is important to investigate the specific regulatory pathways that activate the different Notch receptors. There was a time- and dose-dependent activation of Notch1 by angiotensin II and platelet-derived growth factor in vascular smooth muscle cells. When phospholipase Cγ1 (PLCγ1) expression was reduced by small interfering RNA, Notch1 activation and Hey2 expression (Notch target gene) induced by angiotensin II or platelet-derived growth factor were remarkably inhibited, while Notch2 degradation was not affected. Mechanistically, we observed an association of PLCγ1 and Akt, which increased after angiotensin II or platelet-derived growth factor stimulation. PLCγ1 knockdown significantly inhibited Akt activation. Importantly, PLCγ1 phospholipase site mutation (no phospholipase activity) did not affect Akt activation. Furthermore, PLCγ1 depletion inhibited platelet-derived growth factor-induced vascular smooth muscle cell proliferation, migration, and dedifferentiation, while it increased apoptosis. In vivo, PLCγ1 and control small interfering RNA were delivered periadventitially in pluronic gel and complete carotid artery ligation was performed. Morphometric analysis 21 days after ligation demonstrated that PLCγ1 small interfering RNA robustly attenuated intima area and intima/media ratio compared with the control group. PLCγ1-Akt-mediated Notch1 signaling is crucial for intima formation. This effect is attributable to PLCγ1-Akt interaction but not PLCγ1 phospholipase activity. Specific inhibition of the PLCγ1 and Akt interaction will be a promising therapeutic strategy for preventing vascular remodeling. Show less

Hepatitis E virus- (HEV-) mediated hepatitis has become a global public health problem. An important regulatory protein of HEV, ORF3, influences multiple signal pathways in host cells. In this study, to investigate the function of ORF3 from the swine form of HEV (SHEV), high-throughput RNA-Seq-based screening was performed to identify the differentially expressed genes in ORF3-expressing HepG2 cells. The results were validated with quantitative real-time PCR and gene ontology was employed to assign differentially expressed genes to functional categories. The results indicated that, in the established ORF3-expressing HepG2 cells, the mRNA levels of CLDN6, YLPM1, APOC3, NLRP1, SCARA3, FGA, FGG, FGB, and FREM1 were upregulated, whereas the mRNA levels of SLC2A3, DKK1, BPIFB2, and PTGR1 were downregulated. The deregulated expression of CLDN6 and FREM1 might contribute to changes in integral membrane protein and basement membrane protein expression, expression changes for NLRP1 might affect the apoptosis of HepG2 cells, and the altered expression of APOC3, SCARA3, and DKK1 may affect lipid metabolism in HepG2 cells. In conclusion, ORF3 plays a functional role in virus-cell interactions by affecting the expression of integral membrane protein and basement membrane proteins and by altering the process of apoptosis and lipid metabolism in host cells. These findings provide important insight into the pathogenic mechanism of HEV. Show less

Papillary thyroid carcinoma (PTC) is the most common type of thyroid carcinoma, and our understanding of its pathogenesis is incomplete. To elucidate the mechanisms underlying such progression and identify novel diagnostic markers, we aimed to discover the underlying gene associated with PTC. Integrated analysis of microarray datasets was performed to identify differentially expressed genes (DEGs) between PTCs and normal tissues. GO enrichment analysis and KEGG pathway enrichment analysis were then performed to uncover the functions of DEGs. Furthermore, the protein-protein interaction (PPI) network of DEGs was constructed. Five GEO datasets were obtained. Totally, 154 DEGs across the studies were identified, including 26 upregulated and 128 downregulated DEGs. In the PPI network, MLLT1, DLG2, and EFEMP1 were the hub proteins, in which DLG2 and EFEMP1 were involved in tumor progression. Among the top 10 up- and downregulated genes, the dysregulation genes of TPO, CDH16, and MPPED2 may be closely related to the tumorigenesis of PTC. By integrated analysis of multiple gene expression profiles, we propose that the dysregulation genes of TPO and MPPED2 will be the promising diagnostic markers for PTCs. Show less

Inherited cardiomyopathy is the major cause of sudden cardiac death (SCD) and heart failure (HF). The disease is associated with extensive genetic heterogeneity; pathogenic mutations in cardiac sarcomere protein genes, cytoskeletal protein genes and nuclear envelope protein genes have been linked to its etiology. Early diagnosis is conducive to clinical monitoring and allows for presymptomatic interventions as needed. In the present study, the entire coding sequences and flanking regions of 12 major disease (cardiomyopathy)-related genes [namely myosin, heavy chain 7, cardiac muscle, β (MYH7); myosin binding protein C, cardiac (MYBPC3); lamin A/C (LMNA); troponin I type 3 (cardiac) (TNNI3); troponin T type 2 (cardiac) (TNNT2); actin, α, cardiac muscle 1 (ACTC1); tropomyosin 1 (α) (TPM1); sodium channel, voltage gated, type V alpha subunit (SCN5A); myosin, light chain 2, regulatory, cardiac, slow (MYL2); myosin, heavy chain 6, cardiac muscle, α (MYH6); myosin, light chain 3, alkali, ventricular, skeletal, slow (MYL3); and protein kinase, AMP-activated, gamma 2 non-catalytic subunit  (PRKAG2)] in 8 patients with dilated cardiomyopathy (DCM) and in 8 patients with hypertrophic cardiomyopathy (HCM) were amplified and then sequenced using the Ion Torrent Personal Genome Machine (PGM) system. As a result, a novel heterozygous mutation (MYH7, p.Asn885Thr) and a variant of uncertain significance (TNNT2, p.Arg296His) were identified in 2 patients with HCM. These 2 missense mutations, which were absent in the samples obtained from the 200 healthy control subjects, altered the amino acid that was evolutionarily conserved among a number of vertebrate species; this illustrates that these 2 non-synonymous mutations play a role in the pathogenesis of HCM. Moreover, a double heterozygous mutation (PRKAG2, p.Gly100Ser plus MYH7, p.Arg719Trp) was identified in a patient with severe familial HCM, for the first time to the best of our knowledge. This patient provided us with more information regarding the genotype-phenotype correlation between mutations of MYH7 and PRKAG2. Taken together, these findings provide insight into the molecular mechanisms underlying inherited cardiomyopathy. The mutations identified in this study may be further investigated in the future in order to improve the diagnosis and treatment of patients with inherited cardiomyopathy. Furthermore, our findings indicated that sequencing using the Ion Torrent PGM system is a useful approach for the identification of pathogenic mutations associated with inherited cardiomyopathy, and it may be used for the risk evaluation of individuals with a possible susceptibility to inherited cardiomyopathy. Show less

Dengue results in a significant public health burden in endemic regions. The World Health Organization (WHO) recommended the use of warning signs (WS) to stratify patients at risk of severe dengue disease in 2009. However, WS is limited in stratifying adult dengue patients at early infection (Day 1-3 post fever), who require close monitoring in hospitals to prevent severe dengue. The aim of this study is to identify and validate prognostic models, built with differentially expressed biomarkers, that enable the early identification of those with early dengue infection that require close clinical monitoring. RNA microarray and protein assays were performed to identify differentially expressed biomarkers of severity among 92 adult dengue patients recruited at early infection from years 2005-2008. This comprised 47 cases who developed WS after first presentation and required hospitalization (WS+Hosp), as well as 45 controls who did not develop WS after first presentation and did not require hospitalization (Non-WS+Non-Hosp). Independent validation was conducted with 80 adult dengue patients recruited from years 2009-2012. Prognostic models were developed based on forward stepwise and backward elimination estimation, using multiple logistic regressions. Prognostic power was estimated by the area under the receiver operating characteristic curve (AUC). The WS+Hosp group had significantly higher viral load (P<0.001), lower platelet (P<0.001) and lymphocytes counts (P = 0.004) at early infection compared to the Non-WS+Non-Hosp group. From the RNA microarray and protein assays, the top single RNA and protein prognostic models at early infection were CCL8 RNA (AUC:0.73) and IP-10 protein (AUC:0.74), respectively. The model with CCL8, VPS13C RNA, uPAR protein, and with CCL8, VPS13C RNA and platelets were the best biomarker models for stratifying adult dengue patients at early infection, with sensitivity and specificity up to 83% and 84%, respectively. These results were tested in the independent validation group, showing sensitivity and specificity up to 96% and 54.6%, respectively. At early infection, adult dengue patients who later presented WS and require hospitalization have significantly different pathophysiology compared with patients who consistently presented no WS and / or require no hospitalization. The molecular prognostic models developed and validated here based on these pathophysiology differences, could offer earlier and complementary indicators to the clinical WHO 2009 WS guide, in order to triage adult dengue patients at early infection. Show less

Macrophage foam cell formation is the most prominent characteristic of the early stages of atherosclerosis. Ubiquitin Fold Modifier 1 (UFM1) is a new member of the ubiquitin-like protein family, and its underlying mechanism of action in macrophage foam cell formation is poorly understood. Our current study focuses on UFM1 and investigates its role in macrophage foam cell formation. Using real-time quantitative PCR (qRT-PCR) and western blot analysis, we first analyzed the UFM1 expression in mouse peritoneal macrophages (MPMs) from ApoE－/－ mice in vivo and in human macrophages treated with oxLDL in vitro. Subsequently, the effects of UFM1 on macrophages foam cell formation were determined by Nile Red staining and direct lipid analysis. We then examined whether UFM1 affects the process of lipid metabolism in macrophages. Lastly, with the method of small interfering RNA (siRNA), we delineated the mechanism of UFM1 to attenuate lipid accumulation in THP-1 macrophages. UFM1 is dramatically upregulated under atherosclerosis conditions both in vivo and in vitro. Moreover, UFM1 markedly decreased macrophage foam cell formation. Mechanistic studies revealed that UFM1 increased the macrophage cholesterol efflux, which was due to the increased expression of ATP-binding cassette transporters A1 (ABCA1) and G1 (ABCG1). Furthermore, the upregulation of ABCA1 and ABCG1 by UFM1 resulted from liver X receptor α (LXRα) activation, which was confirmed by the observation that LXRα siRNA prevented the expression of ABCA1 and ABCG1. Consistent with this, the UFM1-mediated attenuation of lipid accumulation was abolished by such inhibition. Taken together, our results showed that UFM1 could suppress foam cell formation via the LXRα-dependent pathway. Show less

Myelin regeneration is indispensably important for patients suffering from several central nervous system (CNS) disorders such as multiple sclerosis (MS) and spinal cord injury (SCI), because it is not only essential for restoring neurophysiology, but also protects denuded axons for secondary degeneration. Understanding the cellular and molecular mechanisms underlying remyelination is critical for the development of remyelination-specific therapeutic approaches. As remyelination shares certain common mechanisms with developmental myelination, knowledge from study of developmental myelination contributes greatly to emerging myelin regeneration therapies, best evidenced as the recently developed human anti-Nogo receptor interacting protein-1 (LINGO-1) monoclonal antibodies to treat MS patients in clinical trials. Show less

Statin therapy has affected glucose homoeostasis of type 2 diabetes patients, which could be related with bile acids metabolism. Whether bile acid metabolism and the expression of farnesoid X receptor (FXR), liver X receptor-α (LXR-α) and sterol regulatory element-binding protein (Srebp)-1c is regulated by hyperglycemia, or whether simvastatin therapy led to higher glucose is related with down-regulated expression of FXR in diabetic rats remained unclear. Forty male Wistar rats were randomly divided into four groups: normal control rats, insulin resistance rats, diabetic model rats, and the late simvastatin induced diabetic rats. Normal control rats were fed with standard diet, others were fed with high-fat diet. Diabetic model rats were induced by a single intraperitoneal injection of streptozotocin (STZ). The late simvastatin induced diabetic rats started simvastatin administration after STZ induced diabetic model rats. Characteristics of fasting blood glucose (FPG), lipid files and total bile acids (TBAs) were measured and the oral glucose tolerance test (OGTT) was performed after overnight fasting at the eighth weekend. RNA and protein levels of FXR, LXR-α and Srebp-1c were tested by Western blotting and reverse transcription polymerase chain reaction (RT-PCR). The insulin resistance rats showed higher glucose, lipid files and lower expression of FXR compared with normal control rats (P > 0.05). The diabetic model rats showed significantly higher glucose, lipid files, TBA and lower expression of FXR compared with insulin resistance rats (P < 0.05). The late simvastatin induced diabetic rats displayed higher glucose and TBA and lower expression of FXR compared with diabetic model rats (P < 0.05). Changes in bile acid homeostasis, including the alterations of bile acid levels and bile acid receptors, are either a cause or a consequence of the metabolic disturbances observed during diabetic models. Statin therapy induced hyperglycemia may be related with FXR, SHP, LXR-α and Srebp-1 pathways. Show less

Cholesterol efflux from macrophages is a critical mechanism to prevent the development of atherosclerosis. Here, we sought to investigate the effects of arctigenin, a bioactive component of Arctium lappa, on the cholesterol efflux in oxidized low-density lipoprotein (oxLDL)-loaded THP-1 macrophages. Our data showed that arctigenin significantly accelerated apolipoprotein A-I- and high-density lipoprotein-induced cholesterol efflux in both dose- and time-dependent manners. Moreover, arctigenin treatment enhanced the expression of ATP binding cassette transporter A1 (ABCA1), ABCG1, and apoE, all of which are key molecules in the initial step of cholesterol efflux, at both mRNA and protein levels. Arctigenin also caused a concentration-dependent elevation in the expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and liver X receptor-alpha (LXR-α). The arctigenin-mediated induction of ABCA1, ABCG1, and apoE was abolished by specific inhibition of PPAR-γ or LXR-α using small interfering RNA technology. Our results collectively indicate that arctigenin promotes cholesterol efflux in oxLDL-loaded THP-1 macrophages through upregulation of ABCA1, ABCG1 and apoE, which is dependent on the enhanced expression of PPAR-γ and LXR-α. Show less

Insulin resistance in type 2 diabetes results from a combination of hyperglycemia and elevated free fatty acid (FFA) concentrations. However, the individual effects of glucotoxicity and lipotoxicity on cell function have not been determined. To compare the effects of increased FFAs and glucose levels on the PARP-NAD-SIRT1 pathway, which modulates insulin sensitivity, we cultured HepG2 hepatocytes with 300 or 500 µM oleic acid (OA) or 30 mM glucose for 1-4 days. PARP activity, NAD level, SIRT1 expression and insulin receptor phosphorylation were determined. PARP activity was higher while NAD level and SIRT1 expression were lower in OA-treated cells than in control cells. Insulin receptor phosphorylation in response to insulin stimulation was attenuated under OA stimulation. Compared to glucose, OA produced a more rapid effect on the PARP-NAD-SIRT1 pathway in HepG2 cells. The reduction in SIRT1 expression and insulin receptor phosphorylation was similar in cells treated with 500 μM OA for 1 day and those treated with 30 mM glucose for 4 days. In addition to PARP activation, the LXRα activator T0901317 also affected SIRT1 expression. FFAs modulated cellular function through multiple ways, and induced more rapid and more potent cytotoxicity than glucose. Show less

To explore the mechanism via which the epidermal growth factor (EGF) affects the migration of human amnion-derived mesenchymal stem cells (hAMSCs). In vitro cultured hAMSCs were divided into control (untreated), EGF group, inhibitor AG1478 + EGF group, inhibitor LY294002 + EGF group, and inhibitor U0126 + EGF group. The migration ability of hAMSCs in each group was measured using Transwell chamber. The expressions of phosphorylated EGFR (P-EGFR), phosphorylated AKT (P-AKT), and phosphorylated ERK1/2 (P-ERK1/2) as well as the expressions of metalloproteinase (MMP) -2 and MMP-9 were detected using Western blot analysis. The differentially expressed genes in the culture solutions in EGF groups and control group were analyzed with RNA-Seq technique. Cells in EGF group had significantly stronger migration ability than in control group (P = 0.0361), inhibitor AG1478 + EGF group (P = 0.0113), inhibitor LY294002 + EGF group (P = 0.0169), and inhibitor U0126 + EGF group (P = 0.0293). EGF increased the phosphorylation levels of EGFR, AKT and ERK, and increased the expression of MMP-2. However, the increased expressions of P-AKT and P-ERK could be suppressed by AG1478 and LY294002. As shown by GO functional enrichment analysis and KEGG pathway analysis, EGF increased the transcription of genes, which were mainly involved in transcriptional regulation, protein modification, and apoptosis inhibition. Genes that were involved in the MARK pathway included DUSP5, IL1B, DUSP6, NGF, and HSPA2. EGF-induced migration of hAMSCs may be mediated by the signaling pathways of PI3K and ERK, which needs MMP-2 expression and the co-expression of genes involved in transcriptional regulation, protein modification, and apoptosis inhibition. Show less

The liver X receptors (LXRs) sense oxysterols and regulate genes involved in cholesterol metabolism. Synthetic agonists of LXRs are potent stimulators of fatty acid synthesis, which is mediated largely by sterol regulatory element-binding protein-1c (SREBP-1c). Paradoxically, an improved hepatic lipid profile by LXR was observed in mice fed a Western high fat (HF) diet. To explore the underlying mechanism, we administered mice normal chow or an HF diet and overexpressed LXRalpha in the liver. The HF diet with tail-vein injection of adenovirus of LXRalpha increased the expression of LXR-targeted genes involved in cholesterol reverse transport but not those involved in fatty acid synthesis. A similar effect was also observed with the use of 22R-hydroxycholesterol, an LXR ligand, in cultured hepatocytes. Consequently, SREBP-1c maturation was inhibited by the HF diet, which resulted from the induction of Insig-2a. Importantly, increased cholesterol level suppressed the expression of 2,3-oxidosqualene cyclase (OSC), which led to an increase in endogenous LXR ligand(s). Furthermore, siRNA-mediated knockdown of OSC expression enhanced LXR activity and selectively up-regulated LXR-targeted genes involved in cholesterol reverse transport. Thus, down-regulation of OSC may account for a novel mechanism underlying the LXR-mediated lipid metabolism in the liver of mice fed an HF diet. Show less

Gene expression profiling was performed using the National Institute on Aging 15,000-cDNA microarray to reveal the differential expression pattern of 160 genes between meiotic pachytene spermatocytes and postmeiotic round spermatids of the mouse. Our results indicate that more genes are expressed in spermatids than in spermatocytes. Genes participating in cell cycle regulation and chromatin structure and dynamics are preferentially expressed in spermatocytes, while genes for protein turnover, signal transduction, energy metabolism, and intracellular transport are prevalent in spermatids. This suggests that a switch of functional requirement occurs when meiotic germ cells differentiate into haploid spermatids. Concordant expression patterns were obtained when quantitative real-time polymerase chain reaction was performed to verify the microarray data. Interestingly, the majority of the differentially expressed genes were underrepresented in mitotic type A spermatogonia, and they were preferentially expressed in the testis. Our results suggest that an even higher proportion of the mouse genome is devoted to male gamete development from meiosis than was previously estimated. We also provide evidence that underscores the advantage of using purified germ cells over whole testes in profiling spermatogenic gene expression to identify transcripts that demonstrate stage-specific expression patterns. Show less

The transcriptomes of mouse type A spermatogonia (Spga), pachytene spermatocytes (Spcy), and round spermatids (Sptd) were determined by sequencing the respective SAGE (Serial Analysis of Gene Expression) libraries. A total of 444,015 tags derived from one Spga, two Spcy, and one Sptd library were analyzed, and 34,619 different species of transcripts were identified, 5279 of which were novel. Results indicated the germ-cell transcriptome comprises of more than 30,000 transcripts. Virtual subtraction showed that cell-specific transcripts constitute 12-19.5% of the transcriptome. Components of the protein biosynthetic machinery are highly expressed in Spga. In Spcy transcription factors are abundantly expressed while transcripts encoding proteins involved in chromosome remodeling and testis-specific transcripts are prominent in Sptd. The databases generated by this work provide very useful resources for cellular localization of genes in silico. They are also extremely useful as sources for identification of splice variants of genes in germ cells. Show less

Complementary DNA microarray and quantitative polymerase chain reaction were used as tools for discovering genes that are differentially expressed in the mouse under normal physiological conditions at distinctive stages of male germ cell development, that is, type A spermatogonia, pachytene spermatocytes, and round spermatids. By using this strategy, we identified a set of genes exhibiting differential expression patterns in spermatogenesis, suggesting that specific functions of the encoded products occurred during the developmental process. Among them were several genes previously not known to be active in testis, which signified undiscovered functional roles of these genes during spermatogenesis. Many of the genes identified were not previously characterized. This study highlights new targets for manipulation to unravel the molecular mechanism of spermatogenesis. Show less