WW domains harbor substrates containing proline-rich motifs, but the substrate specificity and binding mechanism remain elusive for those WW domains less amenable for structural studies, such as human Show more
WW domains harbor substrates containing proline-rich motifs, but the substrate specificity and binding mechanism remain elusive for those WW domains less amenable for structural studies, such as human WWP2 (hWWP2). Herein we have employed multiple techniques to investigate the second WW domain (WW2) in hWWP2. Our results show that hWWP2 is a specialized E3 for PPxY motif-containing substrates only and does not recognize other amino acids and phospho-residues. The strongest binding affinity of WW2, and the incompatibility between each WW domain, imply a novel relationship, and our SPR experiment reveals a dynamic binding mode in Class-I WW domains for the first time. The results from alanine-scanning mutagenesis and modeling further point to functionally conserved residues in WW2. Show less
Fibroblast growth factor 21 (FGF21) is a novel metabolic regulator. The present study aimed to investigate the effect of FGF21 on cholesterol efflux and the expression of ATP binding cassette (ABC) A1 Show more
Fibroblast growth factor 21 (FGF21) is a novel metabolic regulator. The present study aimed to investigate the effect of FGF21 on cholesterol efflux and the expression of ATP binding cassette (ABC) A1 and G1 in human THP-1 macrophage-derived foam cells. Furthermore, the present study aimed to investigate the role of the liver X receptor (LXR) α in this process. A model of oxidized low-density lipoprotein-induced foam cells from human THP-1 cells was established. The effect of FGF21 on cholesterol efflux was analyzed using a liquid scintillation counter. The expression of ABCA1 and ABCG1 was determined using quantitative polymerase chain reaction and western blot analyses. FGF21 was found to enhance apolipoprotein A1- and high-density lipoprotein-mediated cholesterol efflux. FGF21 was also observed to increase the mRNA and protein expression of ABCA1 and ABCG1. Furthermore, LXRα-short interfering RNA attenuated the stimulatory effects induced by FGF21. These findings suggest that FGF21 may have a protective effect against atherosclerosis by enhancing cholesterol efflux through the induction of LXRα-dependent ABCA1 and ABCG1 expression. Show less
MYBPC3 dysfunctions have been proven to induce dilated cardiomyopathy, hypertrophic cardiomyopathy, and/or left ventricular noncompaction; however, the genotype-phenotype correlation between MYBPC3 an Show more
MYBPC3 dysfunctions have been proven to induce dilated cardiomyopathy, hypertrophic cardiomyopathy, and/or left ventricular noncompaction; however, the genotype-phenotype correlation between MYBPC3 and restrictive cardiomyopathy (RCM) has not been established. The newly developed next-generation sequencing method is capable of broad genomic DNA sequencing with high throughput and can help explore novel correlations between genetic variants and cardiomyopathies. A proband from a multigenerational family with 3 live patients and 1 unrelated patient with clinical diagnoses of RCM underwent a next-generation sequencing workflow based on a custom AmpliSeq panel, including 64 candidate pathogenic genes for cardiomyopathies, on the Ion Personal Genome Machine high-throughput sequencing benchtop instrument. The selected panel contained a total of 64 genes that were reportedly associated with inherited cardiomyopathies. All patients fulfilled strict criteria for RCM with clinical characteristics, echocardiography, and/or cardiac magnetic resonance findings. The multigenerational family with 3 adult RCM patients carried an identical nonsense MYBPC3 mutation, and the unrelated patient carried a missense mutation in the MYBPC3 gene. All of these results were confirmed by the Sanger sequencing method. This study demonstrated that MYBPC3 gene mutations, revealed by next-generation sequencing, were associated with familial and sporadic RCM patients. It is suggested that the next-generation sequencing platform with a selected panel provides a highly efficient approach for molecular diagnosis of hereditary and idiopathic RCM and helps build new genotype-phenotype correlations. Show less
To investigate the transdifferentiation relationship between eight types of liver cell during rat liver regeneration (LR). 114 healthy Sprague-Dawley (SD) rats were used in this experimental study. Ei Show more
To investigate the transdifferentiation relationship between eight types of liver cell during rat liver regeneration (LR). 114 healthy Sprague-Dawley (SD) rats were used in this experimental study. Eight types of liver cell were isolated and purified with percoll density gradient centrifugation and immunomagentic bead methods. Marker genes for eight types of cell were obtained by retrieving the relevant references and databases. Expression changes of markers for each cell of the eight cell types were measured using microarray. The relationships between the expression profiles of marker genes and transdifferentiation among liver cells were analyzed using bioinformatics. Liver cell transdifferentiation was predicted by comparing expression profiles of marker genes in different liver cells. During LR hepatocytes (HCs) not only express hepatic oval cells (HOC) markers (including PROM1, KRT14 and LY6E), but also express biliary epithelial cell (BEC) markers (including KRT7 and KRT19); BECs express both HOC markers (including GABRP, PCNA and THY1) and HC markers such as CPS1, TAT, KRT8 and KRT18; both HC markers (KRT18, KRT8 and WT1) and BEC markers (KRT7 and KRT19) were detected in HOCs. Additionally, some HC markers were also significantly upregulated in hepatic stellate cells ( HSCs), sinusoidal endothelial cells (SECs) , Kupffer cells (KCs) and dendritic cells (DCs), mainly at 6-72 hours post partial hepatectomy (PH). Our findings indicate that there is a mutual transdifferentiation relationship between HC, BEC and HOC during LR, and a tendency for HSCs, SECs, KCs and DCs to transdifferentiate into HCs. Show less
Rapsyn, a scaffold protein, is required for the clustering of acetylcholine receptors (AChRs) at contacts between motor neurons and differentiating muscle cells. Rapsyn is also expressed in cells that Show more
Rapsyn, a scaffold protein, is required for the clustering of acetylcholine receptors (AChRs) at contacts between motor neurons and differentiating muscle cells. Rapsyn is also expressed in cells that do not express AChRs. However, its function in these cells remains unknown. Here, we show that rapsyn plays an AChR-independent role in organizing the distribution and mobility of lysosomes. In cells devoid of AChRs, rapsyn selectively induces the clustering of lysosomes at high density in the juxtanuclear region without affecting the distribution of other intracellular organelles. However, when the same cells overexpress AChRs, rapsyn is recruited away from lysosomes to colocalize with AChR clusters on the cell surface. In rapsyn-deficient (Rapsn(-/-)) myoblasts or cells overexpressing rapsyn mutants, lysosomes are scattered within the cell and highly dynamic. The increased mobility of lysosomes in Rapsn(-/-) cells is associated with a significant increase in lysosomal exocytosis, as evidenced by increased release of lysosomal enzymes and plasma membrane damage when cells were challenged with the bacterial pore-forming toxin streptolysin-O. These findings uncover a new link between rapsyn, lysosome positioning, exocytosis and plasma membrane integrity. Show less
Genome-wide association studies (GWAS) of chronic obstructive pulmonary disease (COPD) have identified disease-susceptibility loci, mostly in subjects of European descent. We hypothesized that by stud Show more
Genome-wide association studies (GWAS) of chronic obstructive pulmonary disease (COPD) have identified disease-susceptibility loci, mostly in subjects of European descent. We hypothesized that by studying Hispanic populations we would be able to identify unique loci that contribute to COPD pathogenesis in Hispanics but remain undetected in GWAS of non-Hispanic populations. We conducted a metaanalysis of two GWAS of COPD in independent cohorts of Hispanics in Costa Rica and the United States (Multi-Ethnic Study of Atherosclerosis [MESA]). We performed a replication study of the top single-nucleotide polymorphisms in an independent Hispanic cohort in New Mexico (the Lovelace Smokers Cohort). We also attempted to replicate prior findings from genome-wide studies in non-Hispanic populations in Hispanic cohorts. We found no genome-wide significant association with COPD in our metaanalysis of Costa Rica and MESA. After combining the top results from this metaanalysis with those from our replication study in the Lovelace Smokers Cohort, we identified two single-nucleotide polymorphisms approaching genome-wide significance for an association with COPD. The first (rs858249, combined P value = 6.1 × 10(-8)) is near the genes KLHL7 and NUPL2 on chromosome 7. The second (rs286499, combined P value = 8.4 × 10(-8)) is located in an intron of DLG2. The two most significant single-nucleotide polymorphisms in FAM13A from a previous genome-wide study in non-Hispanics were associated with COPD in Hispanics. We have identified two novel loci (in or near the genes KLHL7/NUPL2 and DLG2) that may play a role in COPD pathogenesis in Hispanic populations. Show less
During development, scaffold proteins serve as important platforms for orchestrating signaling complexes to transduce extracellular stimuli into intracellular responses that regulate dendritic spine m Show more
During development, scaffold proteins serve as important platforms for orchestrating signaling complexes to transduce extracellular stimuli into intracellular responses that regulate dendritic spine morphology and function. Axin ("axis inhibitor") is a key scaffold protein in canonical Wnt signaling that interacts with specific synaptic proteins. However, the cellular functions of these protein-protein interactions in dendritic spine morphology and synaptic regulation are unclear. Here, we report that Axin protein is enriched in synaptic fractions, colocalizes with the postsynaptic marker PSD-95 in cultured hippocampal neurons, and interacts with a signaling protein Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in synaptosomal fractions. Axin depletion by shRNA in cultured neurons or intact hippocampal CA1 regions significantly reduced dendritic spine density. Intriguingly, the defective dendritic spine morphogenesis in Axin-knockdown neurons could be restored by overexpression of the small Rho-GTPase Cdc42, whose activity is regulated by CaMKII. Moreover, pharmacological stabilization of Axin resulted in increased dendritic spine number and spontaneous neurotransmission, while Axin stabilization in hippocampal neurons reduced the elimination of dendritic spines. Taken together, our findings suggest that Axin promotes dendritic spine stabilization through Cdc42-dependent cytoskeletal reorganization. Show less
GADD45A is a TP53-regulated and DNA damage-inducible tumor suppressor protein, which regulates cell cycle arrest, apoptosis, and DNA repair, and inhibits tumor growth and angiogenesis. However, the fu Show more
GADD45A is a TP53-regulated and DNA damage-inducible tumor suppressor protein, which regulates cell cycle arrest, apoptosis, and DNA repair, and inhibits tumor growth and angiogenesis. However, the function of GADD45A in autophagy remains unknown. In this report, we demonstrate that GADD45A plays an important role in regulating the process of autophagy. GADD45A is able to decrease LC3-II expression and numbers of autophagosomes in mouse tissues and different cancer cell lines. Using bafilomycin A1 treatment, we have observed that GADD45A regulates autophagosome initiation. Likely, GADD45A inhibition of autophagy is through its influence on the interaction between BECN1 and PIK3C3. Immunoprecipitation and GST affinity isolation assays exhibit that GADD45A directly interacts with BECN1, and in turn dissociates the BECN1-PIK3C3 complex. Furthermore, we have mapped the 71 to 81 amino acids of the GADD45A protein that are necessary for the GADD45A interaction with BECN1. Knockdown of BECN1 can abolish autophagy alterations induced by GADD45A. Taken together, these findings provide the novel evidence that GADD45A inhibits autophagy via impairing the BECN1-PIK3C3 complex formation. Show less
Mammalian milk is a key source of lipids, providing not only important calories but also essential fatty acids. Veterinary medicine and omics systems sciences intersection, termed as "veterinomics" he Show more
Mammalian milk is a key source of lipids, providing not only important calories but also essential fatty acids. Veterinary medicine and omics systems sciences intersection, termed as "veterinomics" here, has received little attention to date but stands to offer much promise for building bridges between human and animal health. We determined the changes in porcine mammary genes and proteomics expression associated with milk triacylglycerol (TAG) synthesis and secretion from late pregnancy to lactation. TAG content and fatty acid (FA) composition were determined in porcine colostrum (the 1st day of lactation) and milk (the 17th day of lactation). The mammary transcriptome for 70 genes and 13 proteins involved in TAG synthesis and secretion from six sows, each at d -17(late pregnancy), d 1(early lactation), and d 17 (peak lactation) relative to parturition were analyzed using quantitative real-time PCR and Western blot analyses. The TAG content and the concentrations of de novo synthesized FAs, saturated FAs, and monounsaturated FAs were higher in milk than in colostrum (p<0.05). Robust upregulation with high relative mRNA abundance was evident during lactation for genes associated with FA uptake (VLDLR, LPL, CD36), FA activation (ACSS2, ACSL3), and intracellar transport (FABP3), de novo FA synthesis (ACACA, FASN), FA elongation (ELOVL1), FA desaturation (SCD, FADS1), TAG synthesis (GPAM, AGPAT1, LPIN1, DGAT1), lipid droplet formation (BTN2A1, XDH, PLIN2), and transcription factors and nuclear receptors (SREBP1, SCAP, INSIG1/2). In conclusion, a wide variety of lipogenic genes and proteins regulate the channeling of FAs towards milk TAG synthesis and secretion in porcine mammary gland tissue. These findings inform future omics strategies to increase milk fat production and lipid profile and attest to the rise of both veterinomics and lipidomics in postgenomics life sciences. Show less
Dual-specificity phosphatase 6 (DUSP6) is a negative feedback mechanism of the mitogen-activated protein (MAP) kinase superfamily (MAPK/ERK, SAPK/JNK, p38), that is associated with cellular proliferat Show more
Dual-specificity phosphatase 6 (DUSP6) is a negative feedback mechanism of the mitogen-activated protein (MAP) kinase superfamily (MAPK/ERK, SAPK/JNK, p38), that is associated with cellular proliferation and differentiation. It has been reported that the expression of DUSP6 in different types of breast cancer is diverse and therefore it has altered functions in various types of breast cancer. Our aim was to explore the exact function of DUSP6 in triple-negative breast cancer cells (MDA-MB-231 cell) and to determine whether the suppression of DUSP6 by small interfering RNA (siRNA) and mircroRNA (miRNA) inhibits the growth of human MDA-MB-231 breast cancer cells. DUSP6-siRNA was used to inhibit the expression of DUSP6 directly and miR-145 to inhibit the expression of DUSP6 either in MDA-MB-231 breast cancer cells and successful transfection being confirmed by Real-time PCR and Western Blotting. Down regulation of DUSP6 in MDA-MB-231 cells suppressed the cell proliferation as investigated by MTT assay and colony form assay. Transwell test and Scratch assay were conducted to investigate the migration and invasion of MDA-MB-231 cells. T-test (two-tailed) was used to compare differences between groups, and the significance level was set at P<0.05. DUSP6 mRNA expression and protein expression were reduced after transfection with DUSP6-siRNA directly and similar trend with transfection with miR-145. The treated group with DUSP6-siRNA or miR-145 suppressed MDA-MB-231 cells proliferation, migration and invasion, and meanwhile the cells were arrested at G0/G1 phase. DUSP6 plays a role in triple-negative breast cancer cells that might promote growth in MDA-MB-231 triple-negative breast cancer cells. Show less
Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone secreted in response to dietary fat and glucose. The blood GIP level is elevated in obesity and diabetes. GIP stimulates proinflamma Show more
Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone secreted in response to dietary fat and glucose. The blood GIP level is elevated in obesity and diabetes. GIP stimulates proinflammatory gene expression and impairs insulin sensitivity in cultured adipocytes. In obesity, hypoxia within adipose tissue can induce inflammation. The aims of this study were 1) to examine the proinflammatory effect of increased GIP signaling in adipose tissues in vivo and 2) to clarify the association between GIP and hypoxic signaling in adipose tissue inflammation. We administered GIP intraperitoneally to misty (lean) and db/db (obese) mice and examined adipose tissue inflammation and insulin sensitivity. We also examined the effects of GIP and hypoxia on expression of the GIP receptor (GIPR) gene and proinflammatory genes in 3T3-L1 adipocytes. GIP administration increased monocyte chemoattractant protein-1 (MCP-1) expression and macrophage infiltration into adipose tissue and increased blood glucose in db/db mice. GIPR and hypoxia-inducible factor-1α (HIF-1α) expressions were positively correlated in the adipose tissue in mice. GIPR expression increased dramatically in differentiated adipocytes. GIP treatment of adipocytes increased MCP-1 and interleukin-6 (IL-6) production. Adipocytes cultured either with RAW 264 macrophages or under hypoxia expressed more GIPR and HIF-1α, and GIP treatment increased gene expression of plasminogen activator inhibitor 1 and IL-6. HIF-1α gene silencing diminished both macrophage- and hypoxia-induced GIPR expression and GIP-induced IL-6 expression in adipocytes. Thus, increased GIP signaling plays a significant role in adipose tissue inflammation and thereby insulin resistance in obese mice, and HIF-1α may contribute to this process. Show less
Familial hypertrophic cardiomyopathy (HCM) is attributed to mutations in genes that encode for the sarcomere proteins, especially Mybpc3 and Myh7. Genotype-phenotype correlation studies show significa Show more
Familial hypertrophic cardiomyopathy (HCM) is attributed to mutations in genes that encode for the sarcomere proteins, especially Mybpc3 and Myh7. Genotype-phenotype correlation studies show significant variability in HCM phenotypes among affected individuals with identical causal mutations. Morphological changes and clinical expression of HCM are the result of interactions with modifier genes. With the exceptions of angiotensin converting enzyme, these modifiers have not been identified. Although mouse models have been used to investigate the genetics of many complex diseases, natural murine models for HCM are still lacking. In this study we show that the DBA/2J (D2) strain of mouse has sequence variants in Mybpc3 and Myh7, relative to widely used C57BL/6J (B6) reference strain and the key features of human HCM. Four-month-old of male D2 mice exhibit hallmarks of HCM including increased heart weight and cardiomyocyte size relative to B6 mice, as well as elevated markers for cardiac hypertrophy including β-myosin heavy chain (MHC), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and skeletal muscle alpha actin (α1-actin). Furthermore, cardiac interstitial fibrosis, another feature of HCM, is also evident in the D2 strain, and is accompanied by up-regulation of type I collagen and α-smooth muscle actin (SMA)-markers of fibrosis. Of great interest, blood pressure and cardiac function are within the normal range in the D2 strain, demonstrating that cardiac hypertrophy and fibrosis are not secondary to hypertension, myocardial infarction, or heart failure. Because D2 and B6 strains have been used to generate a large family of recombinant inbred strains, the BXD cohort, the D2 model can be effectively exploited for in-depth genetic analysis of HCM susceptibility and modifier screens. Show less
To investigate whether activation of liver X receptors (LXRs) protects N-methyl-D-aspartic (NMDA)-induced retinal neurotoxicity in mice and to explore the underlying mechanism. Inner retinal damage wa Show more
To investigate whether activation of liver X receptors (LXRs) protects N-methyl-D-aspartic (NMDA)-induced retinal neurotoxicity in mice and to explore the underlying mechanism. Inner retinal damage was induced by intravitreal injection of NMDA. A synthetic LXR ligand TO901317 (TO90, 50 mg/kg/d) or vehicle was intragastrically administrated from 3 days before to 1 day or 7 days after NMDA injection. The severity of retinal damage was evaluated with histological analysis and TUNEL staining, and retinal functions were evaluated by ERG. The expressions of caspase-3, bax, bcl-2, TNF-α, and BACE1, the rate-limiting enzyme in the formation of amyloid β (Aβ), in the retina were examined by real-time PCR and ELISA. The levels of LXRs, NF-κB subunit p65, p-p38 mitogen-activated protein kinase (MAPK), and an LXR target gene ABCA1 were detected with real-time PCR and Western blotting. The localization and protein expression of Aβ in the retina was assessed by immunohistochemistry and Western blotting. The NMDA enhanced the expression of LXRβ but not LXRα and ABCA1 in mouse retina. Nevertheless, administration of TO90 after NMDA injection not only enhanced the expression of LXRβ but also upregulated the level of ABCA1, suggesting retinal LXRs were activated in a ligand-dependent manner. The LXRα expression was unchanged in the vehicle and the TO90-treated groups. Activation of LXRβ with TO90 inhibited cell death in the ganglion cell layer (GCL) and inner nuclear layer (INL), preserved ERG b- and a-wave amplitudes, and the b/a ratio in the NMDA-treated mice. Meanwhile, TO90 suppressed the elevation of apoptosis factors caspase-3 and bax induced by NMDA and upregulated the level of an antiapoptotic factor bcl-2. The TO90 also inhibited the increase of p-p38 MAPK and proinflammatory cytokine TNF-α after NMDA injection. Furthermore, activation of LXR attenuated the activation of NF-κB, and reduced gene expression of BACE1 and accumulation of Aβ induced by NMDA. Activation of LXRβ with a synthetic LXR ligand TO90 protects the inner retinal damage induced by NMDA in mice. We speculate the protective effect is associated with inhibition of the NF-κB signaling pathway and reduction of Aβ formation in retina. The LXR agonists may become a new class of neuroprotective agent for retinal diseases associated with glutamate-induced excitotoxicity. Show less
The unwinding of nucleic acid secondary structures within cells is crucial to maintain genomic integrity and prevent abortive transcription and translation initiation. DHX36, also known as RHAU or G4R Show more
The unwinding of nucleic acid secondary structures within cells is crucial to maintain genomic integrity and prevent abortive transcription and translation initiation. DHX36, also known as RHAU or G4R1, is a DEAH-box ATP-dependent helicase highly specific for DNA and RNA G-quadruplexes (G4s). A fundamental mechanistic understanding of the interaction between helicases and their G4 substrates is important to elucidate G4 biology and pave the way toward G4-targeted therapies. Here we analyze how the thermodynamic stability of G4 substrates affects binding and unwinding by DHX36. We modulated the stability of the G4 substrates by varying the sequence and the number of G-tetrads and by using small, G4-stabilizing molecules. We found an inverse correlation between the thermodynamic stability of the G4 substrates and rates of unwinding by DHX36. In stark contrast, the ATPase activity of the helicase was largely independent of substrate stability pointing toward a decoupling mechanism akin to what has been observed for many double-stranded DEAD-box RNA helicases. Our study provides the first evidence that DHX36 uses a local, non-processive mechanism to unwind G4 substrates, reminiscent of that of eukaryotic initiation factor 4A (eIF4A) on double-stranded substrates. Show less
Recent genome-wide association studies have identified several loci influencing lipid levels. The present study focused on the triglycerides (TG)-associated locus, the APOA4-APOA5-ZNF259-BUD13 gene cl Show more
Recent genome-wide association studies have identified several loci influencing lipid levels. The present study focused on the triglycerides (TG)-associated locus, the APOA4-APOA5-ZNF259-BUD13 gene cluster on chromosome 11, to explore the role of genetic variants in this gene cluster in the development of increasing TG levels and coronary heart disease (CHD). Six single nucleotide polymorphisms (SNPs), rs4417316, rs651821, rs6589566, rs7396835, rs964184 and rs17119975, in the APOA4-APOA5-ZNF259-BUD13 gene cluster were selected and genotyped in 5374 healthy Chinese subjects. There were strong significant associations between the six SNPs and TG levels (P < 1.0 × 10(-8)). Moreover, a weighted genotype score was found to be associated with TG levels (P = 3.28 × 10(-13)). The frequencies of three common haplotypes were observed to be significantly different between the high TG group and the low TG group (P < 0.05). However, no significant effects were found for the SNPs regarding susceptibility to CHD in the Chinese case-control populations. This study highlights the genotypes, genotype scores and haplotypes of the APOA4-APOA5-ZNF259-BUD13 gene cluster that were associated with TG levels in a Chinese population; however, the genetic variants in this gene cluster did not increase the risk of CHD in the Chinese population. Show less
Glycosaminoglycans are important regulators of multiple signaling pathways. As a major constituent of the heart extracellular matrix, glycosaminoglycans are implicated in cardiac morphogenesis through Show more
Glycosaminoglycans are important regulators of multiple signaling pathways. As a major constituent of the heart extracellular matrix, glycosaminoglycans are implicated in cardiac morphogenesis through interactions with different signaling morphogens. Ext1 is a glycosyltransferase responsible for heparan sulfate synthesis. Here, we evaluate the function of Ext1 in heart development by analyzing Ext1 hypomorphic mutant and conditional knockout mice. Outflow tract alignment is sensitive to the dosage of Ext1. Deletion of Ext1 in the mesoderm induces a cardiac phenotype similar to that of a mutant with conditional deletion of UDP-glucose dehydrogenase, a key enzyme responsible for synthesis of all glycosaminoglycans. The outflow tract defect in conditional Ext1 knockout(Ext1f/f:Mesp1Cre) mice is attributable to the reduced contribution of second heart field and neural crest cells. Ext1 deletion leads to downregulation of FGF signaling in the pharyngeal mesoderm. Exogenous FGF8 ameliorates the defects in the outflow tract and pharyngeal explants. In addition, Ext1 expression in second heart field and neural crest cells is required for outflow tract remodeling. Our results collectively indicate that Ext1 is crucial for outflow tract formation in distinct progenitor cells, and heparan sulfate modulates FGF signaling during early heart development. Show less
Mengyang Liu, Yuanli Chen, Ling Zhang+10 more · 2015 · The Journal of biological chemistry · American Society for Biochemistry and Molecular Biology · added 2026-04-24
Cholesteryl ester transfer protein (CETP) transfers cholesteryl esters from high density lipoprotein to triglyceride-rich lipoproteins. CETP expression can be transcriptionally activated by liver X re Show more
Cholesteryl ester transfer protein (CETP) transfers cholesteryl esters from high density lipoprotein to triglyceride-rich lipoproteins. CETP expression can be transcriptionally activated by liver X receptor (LXR). Etoposide and teniposide are DNA topoisomerase II (Topo II) inhibitors. Etoposide has been reported to inhibit atherosclerosis in rabbits with un-fully elucidated mechanisms. In this study we determined if Topo II activity can influence cholesterol metabolism by regulating hepatic CETP expression. Inhibition of Topo II by etoposide, teniposide, or Topo II siRNA increased CETP expression in human hepatic cell line, HepG2 cells, which was associated with increased CETP secretion and mRNA expression. Meanwhile, inhibition of LXR expression by LXR siRNA attenuated induction of CETP expression by etoposide and teniposide. Etoposide and teniposide induced LXRα expression and LXRα/β nuclear translocation while inhibiting expression of receptor interacting protein 140 (RIP140), an LXR co-repressor. In vivo, administration of teniposide moderately reduced serum lipid profiles, induced CETP expression in the liver, and activated reverse cholesterol transport in CETP transgenic mice. Our study demonstrates a novel function of Topo II inhibitors in cholesterol metabolism by activating hepatic CETP expression and reverse cholesterol transport. Show less
Inflammation and lipids play significant roles in the progression of chronic kidney disease. This study was designed to investigate whether inflammation disrupts cellular cholesterol homeostasis and c Show more
Inflammation and lipids play significant roles in the progression of chronic kidney disease. This study was designed to investigate whether inflammation disrupts cellular cholesterol homeostasis and causes the lipid nephrotoxicity in vitro and in vivo, and explored its underlying mechanisms. Inflammatory stress was induced by cytokines (interleukin-1β (IL-1β); tumor necrosis factor α (TNF-α)) to human mesangial cells (HMCs) in vitro and by subcutaneous casein injection in C57BL/6J mice in vivo. The data showed that inflammatory stress exacerbated renal cholesterol ester accumulation in vitro and in vivo. Inflammation increased cellular cholesterol uptake and synthesis via upregulating the expression of low-density lipoprotein receptor (LDLr) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCoA-R), while it decreased cholesterol efflux via downregulating the expression of liver X receptor alpha and ATP-binding cassette transporter A1. The increased lipid accumulation by inflammatory stress induced reactive oxygen species (ROS) and increased levels of endoplasmic reticulum (ER) stress markers (inositol-requiring protein 1 and activating transcription factor 6) in HMCs and kidneys of C57BL/6J mice. This study implied that inflammation promoted renal lipid accumulation and foam cell formation by disrupting cellular cholesterol homeostasis. Increased intracellular lipids under inflammatory stress caused oxidative stress and ER stress in vitro and in vivo which may contribute to renal injury and progression of chronic kidney disease. Show less
In this study, 796 male Duroc pigs were used to identify genomic regions controlling growth traits. Three production traits were studied: food conversion ratio, days to 100 KG, and average daily gain, Show more
In this study, 796 male Duroc pigs were used to identify genomic regions controlling growth traits. Three production traits were studied: food conversion ratio, days to 100 KG, and average daily gain, using a panel of 39,436 single nucleotide polymorphisms. In total, we detected 11 genome-wide and 162 chromosome-wide single nucleotide polymorphism trait associations. The Gene ontology analysis identified 14 candidate genes close to significant single nucleotide polymorphisms, with growth-related functions: six for days to 100 KG (WT1, FBXO3, DOCK7, PPP3CA, AGPAT9, and NKX6-1), seven for food conversion ratio (MAP2, TBX15, IVL, ARL15, CPS1, VWC2L, and VAV3), and one for average daily gain (COL27A1). Gene ontology analysis indicated that most of the candidate genes are involved in muscle, fat, bone or nervous system development, nutrient absorption, and metabolism, which are all either directly or indirectly related to growth traits in pigs. Additionally, we found four haplotype blocks composed of suggestive single nucleotide polymorphisms located in the growth trait-related quantitative trait loci and further narrowed down the ranges, the largest of which decreased by ~60 Mb. Hence, our results could be used to improve pig production traits by increasing the frequency of favorable alleles via artificial selection. Show less
Ammonia detoxification is essential for physiological well-being, and the urea cycle in liver plays a predominant role in ammonia disposal. Nobiletin (NOB), a natural dietary flavonoid, is known to ex Show more
Ammonia detoxification is essential for physiological well-being, and the urea cycle in liver plays a predominant role in ammonia disposal. Nobiletin (NOB), a natural dietary flavonoid, is known to exhibit various physiological efficacies. In the current study, we investigated a potential role of NOB in ammonia control and the underlying cellular mechanism. C57BL/6 mice were fed with regular chow (RC), high-fat (HFD) or high-protein diet (HPD) and treated with either vehicle or NOB. Serum and/or urine levels of ammonia and urea were measured. Liver expression of genes encoding urea cycle enzymes and C/EBP transcription factors was determined over the circadian cycle. Luciferase reporter assays were carried out to investigate function of CCAAT consensus elements on the carbamoyl phosphate synthetase (Cps1) gene promoter. A circadian clock-deficient mouse mutant, Clock (Δ19/Δ19) , was utilized to examine a requisite role of the circadian clock in mediating NOB induction of Cps1. NOB was able to lower serum ammonia levels in mice fed with RC, HFD or HPD. Compared with RC, HFD repressed the mRNA and protein expression of Cps1, encoding the rate-limiting enzyme of the urea cycle. Interestingly, NOB rescued CPS1 protein levels under the HFD condition via induction of the transcription factors C/EBPα and C/EBPβ. Expression of other urea cycle genes was also decreased by HFD relative to RC and again restored by NOB to varying degrees, which, in conjunction with Cps1 promoter reporter analysis, suggested a C/EBP-dependent mechanism for the co-induction of urea cycle genes by NOB. In comparison, HPD markedly increased CPS1 levels relative to RC, yet NOB did not further enrich CPS1 to a significant extent. Using the circadian mouse mutant Clock (Δ19/Δ19) , we also showed that a functional circadian clock, known to modulate C/EBP and CPS1 expression, was required for NOB induction of CPS1 under the HFD condition. NOB, a dietary flavonoid, exhibits a broad activity in ammonia control across varying diets, and regulates urea cycle function via C/EBP-and clock-dependent regulatory mechanisms. Show less
Diego Ploper, Vincent F Taelman, Lidia Robert+7 more · 2015 · Proceedings of the National Academy of Sciences of the United States of America · National Academy of Sciences · added 2026-04-24
Canonical Wnt signaling plays an important role in development and disease, regulating transcription of target genes and stabilizing many proteins phosphorylated by glycogen synthase kinase 3 (GSK3). Show more
Canonical Wnt signaling plays an important role in development and disease, regulating transcription of target genes and stabilizing many proteins phosphorylated by glycogen synthase kinase 3 (GSK3). We observed that the MiT family of transcription factors, which includes the melanoma oncogene MITF (micropthalmia-associated transcription factor) and the lysosomal master regulator TFEB, had the highest phylogenetic conservation of three consecutive putative GSK3 phosphorylation sites in animal proteomes. This finding prompted us to examine the relationship between MITF, endolysosomal biogenesis, and Wnt signaling. Here we report that MITF expression levels correlated with the expression of a large subset of lysosomal genes in melanoma cell lines. MITF expression in the tetracycline-inducible C32 melanoma model caused a marked increase in vesicular structures, and increased expression of late endosomal proteins, such as Rab7, LAMP1, and CD63. These late endosomes were not functional lysosomes as they were less active in proteolysis, yet were able to concentrate Axin1, phospho-LRP6, phospho-β-catenin, and GSK3 in the presence of Wnt ligands. This relocalization significantly enhanced Wnt signaling by increasing the number of multivesicular bodies into which the Wnt signalosome/destruction complex becomes localized upon Wnt signaling. We also show that the MITF protein was stabilized by Wnt signaling, through the novel C-terminal GSK3 phosphorylations identified here. MITF stabilization caused an increase in multivesicular body biosynthesis, which in turn increased Wnt signaling, generating a positive-feedback loop that may function during the proliferative stages of melanoma. The results underscore the importance of misregulated endolysosomal biogenesis in Wnt signaling and cancer. Show less
Sesame seed is rich in sesamin. The present study was to (i) investigate the plasma cholesterol-lowering activity of dietary sesamin and (ii) examine the interaction of dietary sesamin with the gene e Show more
Sesame seed is rich in sesamin. The present study was to (i) investigate the plasma cholesterol-lowering activity of dietary sesamin and (ii) examine the interaction of dietary sesamin with the gene expression of sterol transporters, enzymes, receptors, and proteins involved in cholesterol metabolism. Thirty hamsters were divided into three groups fed the control diet (CON) or one of two experimental diets containing 0.2% (SL) and 0.5% (SH) sesamin, respectively, for 6 weeks. Plasma total cholesterol (TC) levels in hamsters given the CON, SL, and SH diets were 6.62 ± 0.40, 5.32 ± 0.40, and 5.00 ± 0.44 mmol/L, respectively, indicating dietary sesamin could reduce plasma TC in a dose-dependent manner. Similarly, the excretion of total fecal neutral sterols was dose-dependently increased with the amounts of sesamin in diets (CON, 2.65 ± 0.57; SL, 4.30 ± 0.65; and SH, 5.84 ± 1.27 μmol/day). Addition of sesamin into diets was associated with down-regulation of mRNA of intestinal Niemann-Pick C1 like 1 protein (NPC1L1), acyl-CoA:cholesterol acyltransferase 2 (ACAT2), microsomal triacylglycerol transport protein (MTP), and ATP-binding cassette transporters subfamily G members 5 and 8 (ABCG5 and ABCG8). Results also showed that dietary sesamin could up-regulate hepatic cholesterol-7α-hydroxylase (CYP7A1), whereas it down-regulated hepatic 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase and liver X receptor alpha (LXRα). It was concluded that the cholesterol-lowering activity of sesamin was mediated by promoting the fecal excretion of sterols and modulating the genes involved in cholesterol absorption and metabolism. Show less
Adjuvant chemotherapy (ACT) is used after surgery to prevent recurrence or metastases. However, ACT for non-small cell lung cancer (NSCLC) is still controversial. This study aimed to develop predictio Show more
Adjuvant chemotherapy (ACT) is used after surgery to prevent recurrence or metastases. However, ACT for non-small cell lung cancer (NSCLC) is still controversial. This study aimed to develop prediction models to distinguish who is suitable for ACT (ACT-benefit) and who should avoid ACT (ACT-futile) in NSCLC. We identified the ACT correlated gene signatures and performed several types of ANN algorithms to construct the optimal ANN architecture for ACT benefit classification. Reliability was assessed by cross-data set validation. We obtained 2 probes (2 genes) with T-stage clinical data combination can get good prediction result. These genes included 208893_s_at (DUSP6) and 204891_s_at (LCK). The 10-fold cross validation classification accuracy was 65.71%. The best result of ANN models is MLP14-8-2 with logistic activation function. Using gene signature profiles to predict ACT benefit in NSCLC is feasible. The key to this analysis was identifying the pertinent genes and classification. This study maybe helps reduce the ineffective medical practices to avoid the waste of medical resources. Show less
Whether polymorphisms rs11856808 and rs9652490 of the Leucine-rich repeat and Ig domain containing, Nogo receptor-interacting protein-1 (LINGO1) gene, as well as rs10968280, rs13362909 and rs7033345 o Show more
Whether polymorphisms rs11856808 and rs9652490 of the Leucine-rich repeat and Ig domain containing, Nogo receptor-interacting protein-1 (LINGO1) gene, as well as rs10968280, rs13362909 and rs7033345 of the LINGO2 gene, increase the risk for Parkinson's disease (PD) is controversial. Considering the overlap of the clinical and pathological characteristics among PD and multiple system atrophy (MSA), we explored the associations between these five polymorphisms and PD and MSA in a Chinese population. A total of 1055 PD patients, 320 MSA patients, and 810 healthy controls (HCs) were genotyped for these five polymorphisms in LINGO1 and LINGO 2 using Sequenom iPLEX Assay technology. Moreover, after combining our results with available published data, a meta-analysis was conducted to investigate the associations between LINGO 1 rs11856808 and rs9652490 and the risk of PD. The frequency of the minor alleles "T" of LINGO1 rs11856808 was significantly lower in PD than that in HCs (p = 0.011, OR 0.89, 95 % CI 0.81-0.97), but not in MSA. Moreover, there were no significant differences in the minor allele frequency distributions of the other four polymorphisms between PD and HCs, and between MSA and HCs. The meta-analysis showed a lack of association of rs9652490 and PD, regardless of the genetic model or ethnic origin. However, the rs11856808 allele decreased the risk of PD in patients of Asian origin in a dominant genetic model. Our findings suggest that rs11856808 plays a protective role by decreasing the risk for PD, but not for MSA, in Asian population, the other four polymorphisms do not contribute to the risk for PD and MSA. Show less
Persistent neuroadaptations following chronic psychostimulant exposure include reduced striatal dopamine D2 receptor (D2R) levels. The signaling of D2Rs is initiated by Gαi/o proteins and terminated b Show more
Persistent neuroadaptations following chronic psychostimulant exposure include reduced striatal dopamine D2 receptor (D2R) levels. The signaling of D2Rs is initiated by Gαi/o proteins and terminated by regulator of G protein signaling (RGS) proteins. The purpose of this study is to examine the association of the drug taking behavior and gene expression profile of D2/D3Rs, and their associated signaling proteins in the ventral tegmental area (VTA) and nucleus accumbens (NAc) using a rodent model of amphetamine (AMPH) self-administration. Rats were allowed to self-administer AMPH (0.187 mg/kg/infusion for a maximum of 40 injections in 6h daily sessions) for 5 days during which rats showed an escalated rate of AMPH intake across days. AMPH self-administration induced profound brain region-dependent alterations of the targeted genes. There was a positive correlation of the messenger ribonucleic acid (mRNA) levels of RGS10 between the VTA and the NAc in the control animals, which was abolished by AMPH self-administration. AMPH self-administration also produced a negative correlation of the mRNA levels of RGS7 and RGS19 between the two brain regions, which was not present in the control group. Furthermore, AMPH taking behavior was associated with changes in certain gene expression levels. The mRNA levels of RGS2 and RGS4 in both the VTA and NAc were positively correlated with the rate of AMPH intake. Additionally, the rate of AMPH intake was also positively correlated with RGS10 and negatively correlated with RGS17 and the short form of D2Rs mRNA level in the VTA. Although there were significant changes in the mRNA levels of RGS7 and RGS8 in the NAc, none of these measures were correlated with the rate of AMPH intake. The present study suggested that short-term AMPH self-administration produced pronounced changes in the VTA that were more associated with AMPH taking behavior than changes in the NAc. Show less
The objective of this study was to investigate the multiple relations between the preliminary molecular structural characteristics and antioxidant activities of polysaccharides from Canarium album (Lo Show more
The objective of this study was to investigate the multiple relations between the preliminary molecular structural characteristics and antioxidant activities of polysaccharides from Canarium album (Lour.) Raeusch (CPS). Three polysaccharide fractions, CPS1, CPS2, and CPS3, were isolated from CPS by column chromatography. CPS1 and CPS3 were mainly composed of neutral polysaccharides linked by α- and β-glycosidic linkages while CPS2 was pectin polysaccharides mainly linked by β-glycosidic linkages. According to the SEC-MALLS-RI system, the molecular weight of CPS1 was greater compared to CPS2 and CPS3, and the molecular weight and radius of CPS did not display positive correlation. The chain conformation analysis indicated CPS1 and CPS2 were typical highly branched polysaccharides while CPS3 existed as a globular shape in aqueous. Furthermore, the antioxidant activity of CPS2 was better than that of CPS3, while that of CPS1 was the weakest. The antioxidant activities of polysaccharide fractions were affected by their monosaccharide composition, glycosidic linkage, molecular weight, and chain conformation. This functional property was a result of a combination of multiple molecular structural factors. CPS2 was the major antioxidant component of CPS and it could be exploited as a valued antioxidant product. The molecular structural characteristics, antioxidant activities, and structure-function relationships of polysaccharide fractions from Canarium album were first investigated in this study. The results provided background and practical knowledge for the deep-processed products of C. album with high added value. CPS2 was the major antioxidant component of CPS, which could be exploited as a valued antioxidant ingredient in food and pharmaceutical industries. Show less
The additional mutational complexity associated with copy number variation (CNV) can provide important clues as to the underlying mechanisms of CNV formation. Correct annotation of the additional muta Show more
The additional mutational complexity associated with copy number variation (CNV) can provide important clues as to the underlying mechanisms of CNV formation. Correct annotation of the additional mutational complexity is, however, a prerequisite for establishing the mutational mechanism. We illustrate this point through the characterization of a novel ∼230 kb EXT1 duplication CNV causing autosomal dominant hereditary multiple osteochondromas. Whole-genome sequencing initially identified the CNV as having a 22-bp insertion at the breakpoint junction and, unprecedentedly, multiple breakpoint-flanking micromutations on both sides of the duplication. Further investigation revealed that this genomic rearrangement had a duplication-inverted triplication-duplication structure, the inverted triplication being a 41-bp sequence synthesized from a nearby template. This permitted the identification of the sequence determinants of both the initiation (an inverted Alu repeat) and termination (a triplex-forming sequence) of break-induced replication and suggested a possible model for the repair of replication-associated double-strand breaks. Show less
Cell reprogramming mediated by histone methylation and demethylation is crucial for the activation of the embryonic genome in early embryonic development. In this study, we employed quantitative real- Show more
Cell reprogramming mediated by histone methylation and demethylation is crucial for the activation of the embryonic genome in early embryonic development. In this study, we employed quantitative real-time polymerase chain reaction (qRT-PCR) to detect mRNA levels and expression patterns of all known histone demethylases in early germinal vesicle stage and in vitro-matured metaphase II (MII) oocytes (which are commonly used as donor cells for nuclear transfer). On screening, the Jumonji domain containing 1C (JMJD1C) gene had the highest level of expression and hence was used for subsequent experiments. We also found that JMJD1C was primarily expressed in the nucleus and showed relatively high levels of expression at the 2-cell, 4-cell, 8-cell, 16-cell, morula, and blastocyst stages of embryos developed from MII oocytes fertilized in vitro. Further, we knocked down the JMJD1C gene in MII oocytes using siRNA and monitored the cleavage of zygotes and development of early embryos after in vitro fertilization. The results showed that the zygote cleavage and blastocyst rates of the transfection group were reduced by 57.1 ± 0.07 and 50 ± 0.01% respectively, which were significantly lower than those of the negative control group (P < 0.05). These data suggest that JMJD1C plays a key role in the normal development of early bovine embryos. Our results also provide a theoretical basis for the investigation of the role and molecular mechanism of histone demethylation in the early development of bovine embryos. Show less
WWP2 is a ubiquitin E3 ligase belonging to the Nedd4-like family. Given that WWP2 target proteins including PTEN that are crucial for regulating cell proliferation or suppressing tumorigenesis, we hav Show more
WWP2 is a ubiquitin E3 ligase belonging to the Nedd4-like family. Given that WWP2 target proteins including PTEN that are crucial for regulating cell proliferation or suppressing tumorigenesis, we have asked whether WWP2 plays a role in controlling cell cycle progression. Here we report that WWP2 is necessary for normal cell cycle progression as its silencing significantly reduces the cell proliferation rate. We have identified that an isoform of WWP2 (WWP2-V4) is highly expressed in the M phase of the cell cycle. Silencing of WWP2 accelerates the turnover of cyclin E, which is accompanied by increased levels of phospho-histone H3 (p-H3) and cyclin B. Moreover, silencing of WWP2 results in compromised phosphorylation of Akt(S473), a residue whose phosphorylation is tightly associated with the activation of the kinase. Combined, these results strongly suggest that WWP2 is an important component in regulating the Akt signaling cascade, as well as cell cycle progression. Show less