👤 Manyu Dong

Hypertriglyceridemia results from increased production and decreased clearance of triglyceride-rich very low-density lipoproteins, a pathological condition that accounts for heightened risk of ischemic vascular diseases in obesity and type 2 diabetes. Despite its intimate association with insulin resistance, whether hypertriglyceridemia constitutes an independent risk for beta cell dysfunction in diabetes is unknown. Answering this fundamental question is stymied by the fact that hypertriglyceridemia is intertwined with hyperglycemia and insulin resistance in obese and diabetic subjects. To circumvent this limitation, we took advantage of apolipoprotein C3 (ApoC3)-transgenic mice, a model with genetic predisposition to hypertriglyceridemia. We showed that ApoC3-transgenic mice, as opposed to age/sex-matched wild-type littermates, develop hypertriglyceridemia with concomitant elevations in plasma cholesterol and non-esterified fatty acid levels. Anti-insulin and anti-glucagon dual immunohistochemistry in combination with morphometric analysis revealed that ApoC3-transgenic and wild-type littermates had similar beta cell and alpha cell masses as well as islet size and architecture. These effects correlated with similar amplitudes of glucose-stimulated insulin secretion and similar degrees of postprandial glucose excursion in ApoC3-transgenic versus wild-type littermates. Oil Red O histology did not visualize lipid infiltration into islets, correlating with the lack of ectopic triglyceride and cholesterol depositions in the pancreata of ApoC3-transgenic versus wild-type littermates. ApoC3-transgenic mice, despite persistent hypertriglyceridemia, maintained euglycemia under both fed and fasting conditions without manifestation of insulin resistance and fasting hyperinsulinemia. Thus, hypertriglyceridemia per se is not an independent risk factor for beta cell dysfunction in ApoC3 transgenic mice. Show less

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease which represents a wide spectrum of hepatic damage. Several studies have reported that NAFLD is a strong independent risk factor for coronary artery disease (CAD). And patients with NAFLD are at higher risk and suggested undergoperiodic cardiovascular risk assessment. Cardiovascular disease (CVD) is responsible for the main cause of death in patients with NAFLD, and is mostly influenced by genetic factors. Both NAFLD and CAD are heterogeneous disease. Common pathways involved in the pathogenesis of NAFLD and CAD includes insulin resistance (IR), atherogenic dyslipidemia, subclinical inflammation, oxidative stress, etc. Genomic characteristics of these two diseases have been widely studied, further research about the association of these two diseases draws attention. The gene polymorphisms of adiponectin-encoding gene (ADIPOQ), leptin receptor (LEPR), apolipoprotein C3 (APOC3), peroxisome proliferator-activated receptors (PPAR), sterol regulatory elementbinding proteins (SREBP), transmembrane 6 superfamily member 2 (TM6SF2), microsomal triglyceride transfer protein (MTTP), tumor necrosis factors-alpha (TNF-α) and manganese superoxide dismutase (MnSOD) have been reported to be related to NAFLD and CAD. In this review, we aimed to provide an overview of recent insights into the genetic basis of NAFLD and CAD. Show less

It is generally recognized that the inflammatory reaction in glia is one of the important pathological factors in brain ischemic injury. Our previous study has revealed that opening ATP-sensitive potassium (K-ATP) channels could attenuate glial inflammation induced by ischemic stroke. However, the detailed mechanisms are not well known. Primary cultured astrocytes separated from C57BL/6 mice were subjected to oxygen-glucose deprivation (OGD); cellular injuries were determined via observing the changes of cellular morphology and cell viability. MicroRNA (miR) and messenger RNA (mRNA) level was validated by real-time PCR. The interaction between microRNA and the target was confirmed via dual luciferase reporter gene assay. Expressions of proteins and inflammatory cytokines were respectively assessed by western blotting and enzyme-linked immunosorbent assay. OGD resulted in astrocytic damage, which was prevented by K-ATP channel opener nicorandil. Notably, we found that OGD significantly downregulated miR-7 and upregulated Herpud2. Our further study proved that miR-7 targeted Herpud2 3'UTR, which encoded endoplasmic reticulum (ER) stress protein-HERP2. Correspondingly, our results showed that OGD increased the levels of ER stress proteins along with significant elevations of pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β). Pretreatment with nicorandil could remarkably upregulate miR-7, depress the ER-related protein expressions including glucose-regulated protein 78 (GRP78), C/EBP-homologous protein (CHOP), and Caspase-12, and thereby attenuate inflammatory responses and astrocytic damages. These findings demonstrate that opening K-ATP channels protects astrocytes against OGD-mediated neuroinflammation. Potentially, miR-7-targeted ER stress acts as a key molecular brake on neuroinflammation. Show less

Transcription factor carbohydrate responsive element binding protein (ChREBP) promotes glycolysis and lipogenesis in metabolic tissues and cancer cells. ChREBP-α and ChREBP-β, two isoforms of ChREBP transcribed from different promoters, are both transcriptionally induced by glucose. However, the mechanism by which glucose increases ChREBP mRNA levels remains unclear. Here we report that hepatocyte nuclear factor 4 alpha (HNF-4α) is a key transcription factor for glucose-induced ChREBP-α and ChREBP-β expression. Ectopic HNF-4α expression increased ChREBP transcription while knockdown of HNF-4α greatly reduced ChREBP mRNA levels in liver cancer cells and mouse primary hepatocytes. HNF-4α not only directly bound to an E-box-containing region in intron 12 of the ChREBP gene, but also promoted ChREBP-β transcription by directly binding to two DR1 sites and one E-box-containing site of the ChREBP-β promoter. Moreover, HNF-4α interacted with ChREBP-α and synergistically promoted ChREBP-β transcription. Functionally, HNF-4α suppression reduced glucose-dependent ChREBP induction. Increased nuclear abundance of HNF-4α and its binding to cis-elements of ChREBP gene in response to glucose contributed to glucose-responsive ChREBP transcription. Taken together, our results not only revealed the novel mechanism by which HNF-4α promoted ChREBP transcription in response to glucose, but also demonstrated that ChREBP-α and HNF-4α synergistically increased ChREBP-β transcription. Show less

Perfluorooctane sulfonate (PFOS), one persistent organic pollutant, has been widely detected in the environment, wildlife and human. Currently few studies have documented the effects of chronic PFOS exposure on lipid metabolism, especially in aquatic organisms. The underlying mechanisms of hepatotoxicity induced by chronic PFOS exposure are still largely unknown. The present study defined the effects of chronic exposure to low level of PFOS on lipid metabolism using zebrafish as a model system. Our findings revealed a severe hepatic steatosis in the liver of males treated with 0.5μM PFOS as evidenced by hepatosomatic index, histological assessment and liver lipid profiles. Quantitative PCR assay further indicated that PFOS significantly increase the transcriptional expression of nuclear receptors (nr1h3, rara, rxrgb, nr1l2) and the genes associated with fatty acid oxidation (acox1, acadm, cpt1a). In addition, chronic PFOS exposure significantly decreased liver ATP content and serum level of VLDL/LDL lipoprotein in males. Taken together, these findings suggest that chronic PFOS exposure induces hepatic steatosis in zebrafish via disturbing lipid biosynthesis, fatty acid β-oxidation and excretion of VLDL/LDL lipoprotein, and also demonstrate the validity of using zebrafish as an alternative model for PFOS chronic toxicity screening. Show less

This article describes the application of Contour to the design and discovery of a novel, potent, orally efficacious liver X receptor β (LXRβ) agonist (17). Contour technology is a structure-based drug design platform that generates molecules using a context perceptive growth algorithm guided by a contact sensitive scoring function. The growth engine uses binding site perception and programmable growth capability to create drug-like molecules by assembling fragments that naturally complement hydrophilic and hydrophobic features of the protein binding site. Starting with a crystal structure of LXRβ and a docked 2-(methylsulfonyl)benzyl alcohol fragment (6), Contour was used to design agonists containing a piperazine core. Compound 17 binds to LXRβ with high affinity and to LXRα to a lesser extent, and induces the expression of LXR target genes in vitro and in vivo. This molecule served as a starting point for further optimization and generation of a candidate which is currently in human clinical trials for treating atopic dermatitis. Show less

In both animals and plants, messenger (m)RNA export has been shown to contribute to immune response regulation. The Arabidopsis nuclear protein MOS11, along with the nucleoporins MOS3/Nup96/SAR3 and Nup160/SAR1 are components of the mRNA export machinery and contribute to immunity mediated by nucleotide binding leucine-rich repeat immune receptors (NLR). The human MOS11 ortholog CIP29 is part of a small protein complex with three additional members: the RNA helicase DDX39, ALY, and TAF15b. We systematically assessed the biological roles of the Arabidopsis homologs of these proteins in toll interleukin 1 receptor-type NLR (TNL)-mediated immunity using reverse genetics. Although mutations in ALY and DDX39 did not result in obvious defects, taf15b mutation partially suppressed the autoimmune phenotypes of a gain-of-function TNL mutant, snc1. An additive effect on snc1 suppression was observed in mos11-1 taf15b snc1 triple mutant plants, suggesting that MOS11 and TAF15b have independent functions. TAF15b-GFP fusion protein, which fully complemented taf15b mutant phenotypes, localized to nuclei similarly to MOS11. However, it was also targeted to cytosolic granules identified as processing bodies. In addition, we observed no change in SNC1 mRNA levels, whereas less SNC1 protein accumulated in taf15b mutant, suggesting that TAF15b contributes to SNC1 homeostasis through posttranscriptional mechanisms. In summary, this study highlights the importance of posttranscriptional RNA processing mediated by TAF15b in the regulation of TNL-mediated immunity. Show less

The oncogenic herpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV) is known to encode four viral interferon regulatory factors (vIRF1 to -4) to subvert the host antiviral immune response, but their detailed DNA-binding profiles as transcription factors in the host remain uncharacterized. Here, we first performed genome-wide vIRF2-binding site mapping in the human genome using chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq). vIRF2 was capable of binding to the promoter regions of 100 putative target genes. Importantly, we confirmed that vIRF2 can specifically interact with the promoters of the genes encoding PIK3C3, HMGCR, and HMGCL, which are associated with autophagosome formation or tumor progression and metastasis, and regulate their transcription in vivo. The crystal structure of the vIRF2 DNA-binding domain (DBD) (referred to here as vIRF2DBD) showed variable loop conformations and positive-charge distributions different from those of vIRF1 and cellular IRFs that are associated with DNA-binding specificities. Structure-based mutagenesis revealed that Arg82 and Arg85 are required for the in vitro DNA-binding activity of vIRF2DBD and can abolish the transcription regulation function of vIRF2 on the promoter reporter activity of PIK3C3, HMGCR, and HMGCL. Collectively, our study provided unique insights into the DNA-binding potency of vIRF2 and suggested that vIRF2 could act as a transcription factor of its target genes in the host antiviral immune response. The oncogenic herpesvirus KSHV is the etiological agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. KSHV has developed a unique mechanism to subvert the host antiviral immune responses by encoding four homologues of cellular interferon regulatory factors (vIRF1 to -4). However, none of their DNA-binding profiles in the human genome have been characterized until now, and the structural basis for their diverse DNA-binding properties remain poorly understood. In this study, we performed the first genome-wide vIRF2-binding site mapping in the human genome and found vIRF2 can bind to the promoter regions of 100 target cellular genes. X-ray structure analysis and functional studies provided unique insights into its DNA-binding potency and regulation of target gene expression. Our study suggested that vIRF2 could act as a transcription factor of its target genes and contribute to KSHV infection and pathogenesis through versatile functions. Show less

Non-obstructive azoospermia (NOA), a severe form of male infertility, is often suspected to be linked to currently undefined genetic abnormalities. To explore the genetic basis of this condition, we successfully sequenced ~650 infertility-related genes in 757 NOA patients and 709 fertile males. We evaluated the contributions of rare variants to the etiology of NOA by identifying individual genes showing nominal associations and testing the genetic burden of a given biological process as a whole. We found a significant excess of rare, non-silent variants in genes that are key epigenetic regulators of spermatogenesis, such as BRWD1, DNMT1, DNMT3B, RNF17, UBR2, USP1 and USP26, in NOA patients (P = 5.5 × 10(-7)), corresponding to a carrier frequency of 22.5% of patients and 13.7% of controls (P = 1.4 × 10(-5)). An accumulation of low-frequency variants was also identified in additional epigenetic genes (BRDT and MTHFR). Our study suggested the potential associations of genetic defects in genes that are epigenetic regulators with spermatogenic failure in human. Show less

The excessive proliferation of vascular smooth muscle cells was key factor in the restenosis of vein graft. And the Notch signaling was demonstrated to regulate vSMC proliferation and differentiation. Soluble Jagged-1 (sJag1) can inhibit Notch signaling in vitro and in vivo; however, its capacity to suppress restenosis of vein graft remains unknown. Under the microscope, the left jugular vein of these rats was interposed into the left common carotid artery, followed without any treatment (control), or with Ad-Jag1 (treatment) or placebo (DMSO) post operation. We showed that Ad-Jag1 can attenuate restenosis of vein graft by inducing decreased proliferation and increased apoptosis in vivo. Notch1-Hey2 signaling is critical for the development of intima thickening by controlling vSMC-fate determination. By blocking Notch signaling, Ad-Jag1 can significantly inhibit intima thickening. These studies identify that Ad-Jag1 can restore the vSMC phenotype and inhibit the vSMC proliferation by suppression of Notch1 signaling, and thus open a new avenue for the treatment of restenosis in vein graft. Show less

The liver X receptors (LXRs) are important regulators of lipid, cholesterol, and glucose homeostasis by transcriptional regulation of many key genes in these processes, and the transcriptional activities of LXRs are finely controlled by cooperating with retinoid X receptors and many other coregulators. Here, we report that the LIM protein Ajuba binds to the hinge and the ligand binding domains of LXRα via its C-terminal tandem LIM motifs and enhances LXR target gene expression in liver cells. Depletion of Ajuba in HepG2 cells and in mouse primary hepatocytes decreases LXR target gene expression, whereas stable expression of Ajuba in HepG2 cells results in increased expression of these genes. Mechanistic investigations found that Ajuba selectively interacts with LXRα/retinoid X receptor-γ heterodimer to form a ternary complex, which displays a higher transactivation activity to LXR target genes. Moreover, Ajuba and LXR mutually affect their DNA binding activity at endogenous target chromatins and the cooperation between Ajuba and LXRα is dependent on the functional LXR response elements located in the target promoters. Together, our studies demonstrate that Ajuba is a novel coactivator for LXRs and may play important role in lipid and glucose metabolism. Show less

Rhus verniciflua stokes (RVS) is a popular medicinal plant in oriental medicines which is commonly used to resolve extravasated blood. To elucidate the molecular mechanism of the role of RVS extracts on the regulation of lipid and cholesterol biosynthesis, we investigated whether RVS extract protect the hyperlipidemia in western diet-induced C57BL6/J mice. Mice fed a western diet and additionally RVS extracts was administered orally at a dose of 0.1 or 1 g/kg/day for 2 weeks respectively. Group with higher dose of RVS extract showed a significantly decreased body weight compared with western diet fed mice groups. And total cholesterol, LDL-cholesterol levels and fatty liver formation were also improved especially in group of mice fed western diet supplemented high dose RVS extracts. Next, synthesis of hepatic bile acids were significantly increased in RVS extract fed groups. Furthermore, RVS extracts significantly increase promoter activity of Cyp7a1 via up-regulate the transcriptional expression level of LXRα. Our data suggest that RVS extracts could be a potent therapeutic ingredient for prevent a hyperlipidemia via increase of bile acids biosynthesis. Show less

High altitude environments are of particular interest in the studies of local adaptation as well as their implications in physiology and clinical medicine in human. Some Chinese pig breeds, such as Tibetan pig (TBP) that is well adapted to the high altitude and Dahe pig (DHP) that dwells at the moderate altitude, provide ideal materials to study local adaptation to altitudes. Yet, it is still short of in-depth analysis and understanding of the genetic adaptation to high altitude in the two pig populations. In this study we conducted a genomic scan for selective sweeps using FST to identify genes showing evidence of local adaptations in TBP and DHP, with Wuzhishan pig (WZSP) as the low-altitude reference. Totally, we identified 12 specific selective genes (CCBE1, F2RL1, AGGF1, ZFPM2, IL2, FGF5, PLA2G4A, ADAMTS9, NRBF2, JMJD1C, VEGFC and ADAM19) for TBP and six (OGG1, FOXM, FLT3, RTEL1, CRELD1 and RHOG) for DHP. In addition, six selective genes (VPS13A, GNA14, GDAP1, PARP8, FGF10 and ADAMTS16) were shared by the two pig breeds. Among these selective genes, three (VEGFC, FGF10 and ADAMTS9) were previously reported to be linked to the local adaptation to high altitudes in pigs, while many others were newly identified by this study. Further bioinformatics analysis demonstrated that majority of these selective signatures have some biological functions relevant to the altitude adaptation, for examples, response to hypoxia, development of blood vessels, DNA repair and several hematological involvements. These results suggest that the local adaptation to high altitude environments is sophisticated, involving numerous genes and multiple biological processes, and the shared selective signatures by the two pig breeds may provide an effective avenue to identify the common adaptive mechanisms to different altitudes. Show less

This study aimed to investigate the role of fatty acid synthase (FASN) in the epithelial-mesenchymal transition (EMT) of breast cancer cells. MCF-7 cells and MCF-7 cells overexpressing mitogen-activated protein kinase 5 (MCF-7-MEK5) were used in this study. MCF-7-MEK5 cells showed stable EMT characterized by increased vimentin and decreased E-cadherin expression. An In vivo animal model was established using the orthotopic injection of MCF-7 or MCF-7-MEK5 cells. Real-time quantitative PCR and western blotting were used to detect the expression levels of FASN and its downstream proteins liver fatty acid-binding protein (L-FABP) and VEGF/VEGFR-2 in both in vitro and in vivo models (nude mouse tumor tissues). In MCF-7-MEK5 cells, significantly increased expression of FASN was associated with increased levels of L-FABP and VEGF/VEGFR-2. Cerulenin inhibited MCF-7-MEK5 cell migration and EMT, and reduced FASN expression and down-stream proteins L-FABP, VEGF, and VEGFR-2. MCF-7-MEK5 cells showed higher sensitivity to Cerulenin than MCF-7 cells. Immunofluorescence revealed an increase of co-localization of FASN with VEGF on the cell membrane and with L-FABP within MCF-7-MEK5 cells. Immunohistochemistry further showed that increased percentage of FASN-positive cells in the tumor tissue was associated with increased percentages of L-FABP- and VEGF-positive cells and the Cerulenin treatment could reverse the effect. Altogether, our results suggest that FASN is essential to EMT possibly through regulating L-FABP, VEGF and VEGFR-2. This study provides a theoretical basis and potential strategy for effective suppression of malignant cells with EMT. Show less

Free fatty acids (FFAs) are reported to be related to coronary heart disease (CHD); however, some case subjects in those reports suffered from CHD and diabetes mellitus. The aim of this research was to reveal the FFAs as the independent discriminators in non-diabetic CHD patients. The association between FFA concentrations and DNA methylation of carbohydrate response element binding protein (ChREBP) was also investigated, since ChREBP acted as an important regulatory factor in the FFA synthesis. Blood samples were collected after an overnight fast from 60 controls and 68 non-diabetic patients with CHD. Plasma concentrations of glucose, cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL-C) were measured by standard techniques in an automatic biochemical analyzer. Plasma concentrations of nine types of FFAs were determined by high performance liquid chromatography (HPLC). The DNA methylation of ChREBP was detected by direct bisulfate sequencing. In the case group, the concentrations of glucose and HDL-C decreased, while the concentrations of TC, TG, and each FFA significantly increased compared with controls (p < 0.05). By logistic regression analysis, all FFAs except C14:0 were found to be independent risk factors for CHD in non-diabetic patients. No significant differences of clinical chemistry indicators were found between the methylated and unmethylated case groups. Plasma concentrations of FFAs are higher in non-diabetic patients with CHD and are emerging independent discriminators for CHD. High FFA concentrations are expected to play a role even in non-diabetic patients with CHD. Show less

Previous studies have shown that apolipoprotein A5 (APOA5) gene variants are genetic determinants of the concentration of triglycerides, which are a known risk factor for coronary heart disease (CHD). Using the standardized coronary angiography method, 290 CHD patients and 198 non‑CHD controls were recruited from Ningbo Lihuili Hospital. In addition, 331 unrelated healthy volunteers were recruited as healthy controls from Ningbo Ximen Community residents. Three variants of the APOA5 gene, S19W, ‑1131T>C and 553G>T, were analyzed for their association with CHD. Under a dominant inheritance model, ‑1131CT>C was shown to be a CHD risk factor (P=0.030; OR, 1.422; 95% CI, 1.036‑1.952). The single nucleotide polymorphism, 553G>T, was found to correlate with the severity of CHD in males (P=0.032). Meta‑analysis showed that ‑1131T>C was significantly associated with CHD (P<0.0001). By contrast, negative correlations with CHD were observed for S19W and 553G>T. In the present case‑control study, APOA5 gene variants were not found to correlate with the risk of CHD in the populations studied; however, ‑1131CT>C was shown to be a CHD risk factor under a dominant inheritance model. Meta‑analysis showed a significant contribution of ‑1131T>C to the risk of CHD, implying an ethnic difference in APOA5 gene variants. Show less

In the postsynaptic density of glutamatergic synapses, the discs large (DLG)-membrane-associated guanylate kinase (MAGUK) family of scaffolding proteins coordinates a multiplicity of signaling pathways to maintain and regulate synaptic transmission. Postsynaptic density-93 (PSD-93) is the most variable paralog in this family; it exists in six different N-terminal isoforms. Probably because of the structural and functional variability of these isoforms, the synaptic role of PSD-93 remains controversial. To accurately characterize the synaptic role of PSD-93, we quantified the expression of all six isoforms in the mouse hippocampus and examined them individually in hippocampal synapses. Using molecular manipulations, including overexpression, gene knockdown, PSD-93 knock-out mice combined with biochemical assays, and slice electrophysiology both in rat and mice, we demonstrate that PSD-93 is required at different developmental synaptic states to maintain the strength of excitatory synaptic transmission. This strength is differentially regulated by the six isoforms of PSD-93, including regulations of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor-active and inactive synapses, and activity-dependent modulations. Collectively, these results demonstrate that alternative combinations of N-terminal PSD-93 isoforms and DLG-MAGUK paralogs can fine-tune signaling scaffolds to adjust synaptic needs to regulate synaptic transmission. Show less

By 2030, nearly half of Americans will have nonalcoholic fatty liver disease. In part, this epidemic is fueled by the increasing consumption of caloric sweeteners coupled with an innate capacity to convert sugar into fat via hepatic de novo lipogenesis. In addition to serving as substrates, monosaccharides also increase the expression of key enzymes involved in de novo lipogenesis via the carbohydrate response element-binding protein (ChREBP). To determine whether ChREBP is a potential therapeutic target, we decreased hepatic expression of ChREBP with a specific antisense oligonucleotide (ASO) in male Sprague-Dawley rats fed either a high-fructose or high-fat diet. ChREBP ASO treatment decreased plasma triglyceride concentrations compared with control ASO treatment in both diet groups. The reduction was more pronounced in the fructose-fed group and attributed to decreased hepatic expression of ACC2, FAS, SCD1, and MTTP and a decrease in the rate of hepatic triglyceride secretion. This was associated with an increase in insulin-stimulated peripheral glucose uptake, as assessed by the hyperinsulinemic-euglycemic clamp. In contrast, ChREBP ASO did not alter hepatic lipid content or hepatic insulin sensitivity. Interestingly, fructose-fed rats treated with ChREBP ASO had increased plasma uric acid, alanine transaminase, and aspartate aminotransferase concentrations. This was associated with decreased expression of fructose aldolase and fructokinase, reminiscent of inherited disorders of fructose metabolism. In summary, these studies suggest that targeting ChREBP may prevent fructose-induced hypertriglyceridemia but without the improvements in hepatic steatosis and hepatic insulin responsiveness. Show less

Programmed cell death-4 (PDCD4), a selective protein translation inhibitor, has shown proinflammatory effect in some inflammatory diseases, but its roles in obesity remain unestablished. This study aims to investigate the effects of PDCD4 on obesity, inflammation, and insulin resistance. Surprisingly, high-fat diet (HFD)-fed PDCD4-deficient (PDCD4(-/-)) mice exhibited an absolutely lean phenotype together with improved insulin sensitivity. Compared with wild-type obese mice, HFD-fed PDCD4(-/-) mice showed higher energy expenditure, lower epididymal fat weight, and reduced macrophage infiltration inflammatory cytokine secretion in white adipose tissue (WAT). Alleviated hepatic steatosis along with decreased plasma levels of triglyceride and cholesterol was also observed in these mice. Importantly, PDCD4 appeared to disturb lipid metabolism via inhibiting the expression of liver X receptor (LXR)-α, a master modulator of lipid homeostasis, which was elevated in HFD-fed PDCD4(-/-) mice accompanied by upregulation of its target genes and relieved endoplasmic reticulum stress in WAT. These data demonstrate that PDCD4 deficiency protects mice against diet-induced obesity, WAT inflammation, and insulin resistance through restoring the expression of LXR-α, thereby proposing PDCD4 as a potential target for treating obesity-associated diseases. Show less

The protein, thyroid hormone-responsive SPOT 14 homolog (Thrsp), has been reported to be a lipogenic gene in cultured hepatocytes, implicating an important role of Thrsp in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Thrsp expression is known to be regulated by a variety of transcription factors, including thyroid hormone receptor, pregnane X receptor, and constitutive androstane receptor. Emerging in vitro evidence also points to a critical role of liver X receptor (LXR) in regulating Thrsp transcription in hepatocytes. In the present study, we showed that Thrsp was up-regulated in livers of db/db mice and high-fat-diet-fed mice, two models of murine NAFLD. Hepatic overexpression of Thrsp increased triglyceride accumulation with enhanced lipogenesis in livers of C57Bl/6 mice, whereas hepatic Thrsp gene silencing attenuated the fatty liver phenotype in db/db mice. LXR activator TO901317 induced Thrsp expression in livers of wild-type (WT) and LXR-β gene-deficient mice, but not in LXR-α or LXR-α/β double-knockout mice. TO901317 treatment significantly enhanced hepatic sterol regulatory element-binding protein 1c (SREBP-1c) expression and activity in WT mice, but failed to induce Thrsp expression in SREBP-1c gene-deficient mice. Sequence analysis revealed four LXR response-element-like elements and one sterol regulatory element (SRE)-binding site within a -2,468 ∼+1-base-pair region of the Thrsp promoter. TO901317 treatment and LXR-α overexpression failed to induce, whereas overexpression of SREBP-1c significantly increased Thrsp promoter activity. Moreover, deletion of the SRE site completely abolished SREBP-1c-induced Thrsp transcription. Thrsp is a lipogenic gene in the liver that is induced by the LXR agonist through an LXR-α-mediated, SREBP-1c-dependent mechanism. Therefore, Thrsp may represent a potential therapeutic target for the treatment of NAFLD. Show less

Carotid plaque is a marker of subclinical atherosclerosis with a genetic component. The aim of this follow-up fine mapping study was to identify candidate genes for carotid plaque within four linkage regions. We successfully genotyped 3712 single nucleotide polymorphisms (SNPs) under the four linkage regions that were previously identified in 100 extended Dominican families. Family-based association tests were performed to investigate their associations with carotid plaque. Promising SNPs were evaluated in an independent population-based subcohort (N=941, 384 Dominicans) from the Northern Manhattan Study (NOMAS). In the family study, evidence for association (p<0.0005) was found regarding several genes (NAV2, EFCAB11/TDP1, AGBL1, PTPN9, LINGO1 and LOC730118), with the strongest association at rs4143999 near EFCAB11/TDP1 (p=0.00001 for carotid presence and 0.00003 for plaque area, multiple testing corrected p≤0.02). The association in AGBL1 and PTPN9 was mainly driven by the families with linkage evidence (p=0.00008-0.00001 and 0.76-0.32, respectively, in the families with and without linkage evidence). However, these associations explained only a small portion of the observed linkage. In NOMAS, replication (p<0.05 in the whole NOMAS subcohort and p<0.10 in the smaller Dominican subcohort) was found for SNPs within/near EFCAB11, NAV2, AGBL1 and other genes. This follow-up study has identified multiple candidate genes for carotid plaque in the Dominican population. Many of these genes have been implicated in neurodegenerative and cardiovascular diseases. Further studies with in-depth re-sequencing are needed to uncover both rare and common functional variants that contribute to the susceptibility to atherosclerosis. Show less

Genetic variation may influence chemotherapy response and overall survival in cancer patients. We conducted a genome-wide scan in 535 advanced-stage non-small cell lung cancer (NSCLC) patients from two independent cohorts (307 from Nanjing and 228 from Beijing). A replication was carried out on an independent cohort of 340 patients from Southeastern China followed by a second validation on 409 patients from the Massachusetts General Hospital (Boston, MA). Consistent associations with NSCLC survival were identified for five single-nucleotide polymorphisms (SNP) in Chinese populations with P values ranging from 3.63 × 10(-5) to 4.19 × 10(-7) in the additive genetic model. The minor allele of three SNPs (rs7629386 at 3p22.1, rs969088 at 5p14.1, and rs3850370 at 14q24.3) were associated with worse NSCLC survival while 2 (rs41997 at 7q31.31 and rs12000445 at 9p21.3) were associated with better NSCLC survival. In addition, rs7629386 at 3p22.1 (CTNNB1) and rs3850370 at 14q24.3 (SNW1-ALKBH1-NRXN3) were further replicated in the Caucasian population. In this three-stage genome-wide association studies, we identified five SNPs as markers for survival of advanced-stage NSCLC patients treated with first-line platinum-based chemotherapy in Chinese Han populations. Two of these SNPs, rs7629386 and rs3850370, could also be markers for survival among Caucasian patients. Show less

Carbamoyl phosphate synthetase 1 (CPS1) is a liver-specific, intramitochondrial, rate-limiting enzyme in the urea cycle. A previous study showed that CPS1 is the antigen for hepatocyte paraffin 1 antibody, a commonly used antibody in surgical pathology practice; and CPS1 expression appears to be down-regulated in liver cancer tissue and cell lines. The aim of this study is to understand how the CPS1 gene is regulated in liver carcinogenesis. In this report, we show that human hepatocellular carcinoma (HCC) cells do not express CPS1, whereas cultured human primary hepatocytes express abundant levels. In addition, CPS1 was silenced or down-regulated in liver tumor tissues compared with the matched noncancerous tissues. The expression of CPS1 in HCC cells was restored with a demethylation agent, 5-azacytidine. We show that two CpG dinucleotides, located near the transcription start site, and a CpG-rich region in the first intron were hypermethylated in HCC cells. The hypermethylation of the two CpG dinucleotides was also detected in HCC tumor tissues compared with noncancerous tissues. Further molecular analysis with mutagenesis indicated that the two CpG dinucleotides play a role in promoter activity of the CPS1 gene. In conclusion, our study demonstrates that DNA methylation is a key mechanism of silencing CPS1 expression in human HCC cells, and CPS1 gene hypermethylation of the two CpG dinucleotides is a potential biomarker for HCC. Show less

Chinese medicine has been proposed as a novel strategy for the prevention of metabolic disorders such as obesity. The present study tested 17 Chinese medicinal herbs were tested for their potential anti-obesity effects. The herbs were evaluated in terms of their abilities to stimulate the transcription of Apolipoprotein A-IV (ApoA-IV) in cultured Caco-2/TC7 enterocytes. The herbs that showed stimulating effects on ApoA-IV transcription were further evaluated in terms of their abilities to reduce the formation of triglyceride in differentiated 3T3-L1 adipocytes. ApoA-IV transcription was stimulated by Rhizoma Alismatis and Radix Angelica Sinensis in a dose- and time-dependent manner in cultured Caco-2/TC7 cells. Moreover, these two herbs reduced the amount of triglyceride in differentiated 3T3-L1 adipocytes. The results suggest that Rhizoma Alistmatis and Radix Angelica Sinensis may have potential anti-obesity effects as they stimulate ApoA-IV transcription and reduce triglyceride formation. Show less

To find out the mechanisms of HBx gene inducing oval cell malignant transformation into hepatoma carcinoma cell. The changes of morphology, cell cycle, differentiated markers, c-myc and TGF-alpha in pEGFP-HBx oval cells strain, which stably expressed HBx gene, were studied by inversion phase contrast microscope and transmission electron microscopy, flow cytometry, periodic acid-schiff (PAS) staining, soft agar growth assay, real-time PCR, immunocytochemistry. pEGFP-oval cells and LE/6 oval cells were used as control groups. (1) The pEGFP-HBx oval cells showed bigger in size with malformed nucleus as compared with control groups. (2) Flow cytometry showed that, in contrast with the control groups, the proportion of pEGFP-HBx oval cells arrested in G0/G1 phase decreased but in S or G2/M phase rose. Moreover, the population of aneuploid cells increased obviously. (3) PAS staining showed that there were many glycogen granules in the cytoplasm of pEGFP-HBx oval cell. (4) The pEGFP-HBx oval cell formed colonies in the soft agar. (5) Compared with the control groups, the expression of HNF-4 alpha, AFP, c-myc and TGF-alpha rose obviously, whereas the expression of CK-7 and CK-19 decreased. And the expression of cps1 mRNA was not in the extent of detection. The HBx gene can provoke abnormal differentiation of oval cell and induce oval cell malignant transformation. Show less

To investigate the expression of liver X receptors (LXR) in hypertrophic myocardium and the effect of LXR agonist T0901317 on angiotensin II (AngII) induced cardiomyocyte hypertrophy. Transverse aortic coarctation (TAC) or sham operation were performed in 2-month-old wide type mice (C57/B6). Two weeks later, the expression of LXR in myocardium was detected by quantitative real-time PCR analysis and Western blot analysis. The effect of LXR agonist T0901317 on AngII-induced hypertrophy in cultured neonatal rat cardiomyocytes was also assessed. Quantitative real-time PCR analysis and Western blot analysis showed that LXRalpha but not LXRbeta expression was upregulated post TAC both at mRNA and protein levels (All P < 0.05). AngII induced increased [(3)H] leucine incorporation and cardiomyocyte hypertrophy were significantly reduced by T0901317 in a dose-dependent manner (P < 0.05). T0901317 also dose-dependently inhibited atrial natriuretic peptide (ANP) gene expression in cardiomyocytes (P < 0.05). Our findings strongly suggest that LXR is a potent mediator of cardiomyocyte hypertrophy and LXR activation could attenuate AngII induced cardiomyocyte hypertrophy in vitro. Show less

Hepatocyte paraffin 1 (Hep Par 1), a murine monoclonal antibody, is widely used in surgical pathology practice to determine the hepatocellular origin of neoplasms. However, identity of the antigen for Hep Par 1 is unknown. The aim of this study was to characterize the Hep Par 1 antigen. To identify the antigen, immunoprecipitation was used to isolate the protein from human liver tissue, and a distinct protein band was detected at approximately 165 kDa. The protein band was also present in small intestinal tissue, but was not present in several other non-liver tissues nor in three human hepatocellular carcinoma cell lines, Huh-7, HepG2, and LH86. The protein was purified and analyzed by mass spectrometry. It was identified as carbamoyl phosphate synthetase 1 (CPS1). CPS1 is a rate-limiting enzyme in urea cycle and is located in mitochondria. We demonstrated that hepatoid tumors (gastric and yolk sac) were immunoreactive with both Hep Par 1 antibody and anti-CPS1 antibody, further confirming the results of mass spectrometric analysis. We found that the three human hepatocellular carcinoma cell lines do not express either CPS1 RNA or protein. We confirmed that the gene was present in these cell lines, suggesting that suppression of CPS1 expression occurs at the transcriptional level. This finding may have relevance to liver carcinogenesis, since poorly differentiated hepatocellular carcinomas exhibit poor to absent immunoreactivity to Hep Par 1. In conclusion, we have identified the antigen for Hep Par 1 antibody as a urea cycle enzyme CPS1. Our results should encourage further investigation of potential role that CPS1 expression plays in liver pathobiology and carcinogenesis. Show less

Apolipoprotein A-V (apoA-V) and apoC-III are exchangeable constituents of VLDL and HDL. ApoA-V counteracts the effect of apoC-III on triglyceride (TG) metabolism with poorly defined mechanisms. To better understand the effects of apoA-V on TG and cholesterol metabolism, we delivered apoA-V cDNA into livers of hypertriglyceridemic APOC3 transgenic mice by adenovirus-mediated gene transfer. In response to hepatic apoA-V production, plasma TG levels were reduced significantly as a result of enhanced VLDL catabolism without alternations in VLDL production. This effect was associated with reduced apoC-III content in VLDL. Increased apoA-V production also resulted in decreased apoC-III and increased apoA-I content in HDL. Furthermore, apoA-V-enriched HDL was associated with enhanced LCAT activity and increased cholesterol efflux. This effect, along with apoE enrichment in HDL, contributed to HDL core expansion and alpha-HDL formation, accounting for significant increases in both the number and size of HDL particles. As a result, apoA-V-treated APOC3 transgenic mice exhibited decreased VLDL-cholesterol and increased HDL-cholesterol levels. ApoA-V-mediated reduction of apoC-III content in VLDL represents an important mechanism by which apoA-V acts to ameliorate hypertriglyceridemia in adult APOC3 transgenic mice. In addition, increased apoA-V levels accounted for cholesterol redistribution from VLDL to larger HDL particles. These data suggest that in addition to its TG-lowering effect, apoA-V plays a significant role in modulating HDL maturation and cholesterol metabolism. Show less

To study the genetic control of plant responses to cold stress, Arabidopsis thaliana mutants were isolated by a screen for mutations that impair cold-induced transcription of the CBF3-LUC reporter gene. We report here the characterization and cloning of a mutated gene, atnup160-1, which causes reduced CBF3-LUC induction under cold stress. atnup160-1 mutant plants display altered cold-responsive gene expression and are sensitive to chilling stress and defective in acquired freezing tolerance. AtNUP160 was isolated through positional cloning and shown to encode a putative homolog of the animal nucleoporin Nup160. In addition to the impaired expression of CBF genes, microarray analysis revealed that a number of other genes important for plant cold tolerance were also affected in the mutants. The atnup160 mutants flower early and show retarded seedling growth, especially at low temperatures. AtNUP160 protein is localized at the nuclear rim, and poly(A)-mRNA in situ hybridization shows that mRNA export is defective in the atnup160-1 mutant plants. Our study suggests that Arabidopsis AtNUP160 is critical for the nucleocytoplasmic transport of mRNAs and that it plays important roles in plant growth and flowering time regulation and is required for cold stress tolerance. Show less