👤 Xin Huang

Studies in animal models and in cultured cells have shown that fatty acids can induce alterations in the DNA methylation of specific genes. There have been no studies of the effects of fatty acid supplementation on the epigenetic regulation of genes in adult humans. We investigated the effect of supplementing renal patients with 4 g daily of either n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) or olive oil (OO) for 8 weeks on the methylation status of individual CpG loci in the 5' regulatory region of genes involved in PUFA biosynthesis in peripheral blood mononuclear cells from men and women (aged 53 to 63 years). OO and n-3 LCPUFA each altered (>10% difference in methylation) 2/22 fatty acid desaturase (FADS)-2 CpGs, while n-3 LCPUFA, but not OO, altered (>10%) 1/12 ELOVL5 CpGs in men. OO altered (>6%) 8/22 FADS2 CpGs and (>3%) 3/12 elongase (ELOVL)-5 CpGs, while n-3 LCPUFA altered (>5%) 3/22 FADS2 CpGs and 2/12 (>3%) ELOVL5 CpGs in women. FADS1 or ELOVL2 methylation was unchanged. The n-3 PUFA supplementation findings were replicated in blood DNA from healthy adults (aged 23 to 30 years). The methylation status of the altered CpGs in FADS2 and ELOVL5 was associated negatively with the level of their transcripts. These findings show that modest fatty acid supplementation can induce altered methylation of specific CpG loci in adult humans, contingent on the nature of the supplement and on sex. This has implications for understanding the effect of fatty acids on PUFA metabolism and cell function. Show less

The aim of this study was to examine the association of the genetic variants in the fatty acid desaturase (FADS) gene cluster with erythrocyte phospholipid fatty acids (PLFA), and their relation to risk for type 2 diabetes mellitus (T2DM) in Han Chinese. Seven hundred and fifty-eight patients with T2DM and 400 healthy individuals were recruited. The erythrocyte PLFA and single-nucleotide polymorphism were determined by standard method. Minor allele homozygotes and heterozygotes of rs174575 and rs174537 had lower PL 20:4 ω-6 levels in healthy individuals. Minor allele homozygotes and heterozygotes of rs174455 in FADS3 gene had lower levels of 22:5 ω-3, 20:4 ω-6, and Δ5desaturase activity in patients with T2DM. Erythrocyte membrane PL 18:3 ω-3 (P for trend = 0.002), 22:5 ω-3 (P for trend < 0.001), ω-3 polyunsaturated fatty acid (P for trend < 0.001), and ω-3:ω-6 (P for trend < 0.001) were significantly inversely associated with risk for T2DM. Genetic variants in the FADS gene cluster are associated with altered erythrocyte PLFAs. High levels of PL 18:3 ω-3, 22:5 ω-3, and total ω-3 polyunsaturated fatty acid were associated with low risk for T2DM. Show less

Cysteine proteases play important roles in pathobiology. Here we reveal that cathepsin K (CatK) has a role in ischaemia-induced neovascularization. Femoral artery ligation-induced ischaemia in mice increases CatK expression and activity, and CatK-deficient mice show impaired functional recovery following hindlimb ischaemia. CatK deficiency reduces the levels of cleaved Notch1 (c-Notch1), Hes1 Hey1, Hey2, vascular endothelial growth factor, Flt-1 and phospho-Akt proteins of the ischaemic muscles. In endothelial cells, silencing of CatK mimicked, whereas CatK overexpression enhanced, the levels of c-Notch1 and the expression of Notch downstream signalling molecules, suggesting CatK contributes to Notch1 processing and activates downstream signalling. Moreover, CatK knockdown leads to defective endothelial cell invasion, proliferation and tube formation, and CatK deficiency is associated with decreased circulating endothelial progenitor cells-like CD31(+)/c-Kit(+) cells in mice following hindlimb ischaemia. Transplantation of bone marrow-derived mononuclear cells from CatK(+/+) mice restores the impairment of neovascularization in CatK(-/-) mice. We conclude that CatK may be a potential therapeutic target for ischaemic disease. Show less

Misfolded proteins of the endoplasmic reticulum (ER) are retrotranslocated to the cytosol and degraded by the proteasome via a process termed ER-associated degradation (ERAD). The precise mechanism of retrotranslocation is unclear. Here, we use several lumenal ERAD substrates targeted for degradation by the ubiquitin ligase HRD1 including SHH (sonic hedgehog) and NHK (null Hong Kong α1-antitrypsin) to study the geometry, organization, and regulation of the HRD1-containing ERAD machinery. We report a new HRD1-associated membrane protein named HERP2, which is homologous to the previously identified HRD1 partner HERP1. Despite sequence homology, HERP2 is constitutively expressed in cells, whereas HERP1 is highly induced by ER stress. We find that these proteins are required for efficient degradation of both glycosylated and nonglycosylated SHH proteins as well as NHK. In cells depleted of HERPs, SHH proteins are largely trapped inside the ER with a fraction of the stabilized SHH protein bound to the HRD1-SEL1L ligase complex. Ubiquitination of SHH is significantly attenuated in the absence of HERPs, suggesting a defect in retrotranslocation. Both HERP proteins interact with HRD1 through a region located in the cytosol. However, unlike its homolog in Saccharomyces cerevisiae, HERPs do not regulate HRD1 stability or oligomerization status. Instead, they help recruit DERL2 to the HRD1-SEL1L complex. Additionally, the UBL domain of HERP1 also seems to have a function independent of DERL2 recruitment in ERAD. Our studies have revealed a critical scaffolding function for mammalian HERP proteins that is required for forming an active retrotranslocation complex containing HRD1, SEL1L, and DERL2. Show less

The fish lateral line (LL) is a mechanosensory system closely related to the hearing system of higher vertebrates, and it is composed of several neuromasts located on the surface of the fish. These neuromasts can detect changes in external water flow, to assist fish in maintaining a stationary position in a stream. In the present study, we identified a novel function of Nogo/Nogo receptor signaling in the formation of zebrafish neuromasts. Nogo signaling in zebrafish, like that in mammals, involves three ligands and four receptors, as well as three co-receptors (TROY, p75, and LINGO-1). We first demonstrated that Nogo-C2, NgRH1a, p75, and TROY are able to form a Nogo-C2 complex, and that disintegration of this complex causes defective neuromast formation in zebrafish. Time-lapse recording of the CldnB::lynEGFP transgenic line revealed that functional obstruction of the Nogo-C2 complex causes disordered morphogenesis, and reduces rosette formation in the posterior LL (PLL) primordium during migration. Consistent with these findings, hair-cell progenitors were lost from the PLL primordium in p75, TROY, and Nogo-C2/NgRH1a morphants. Notably, the expression levels of pea3, a downstream marker of Fgf signaling, and dkk1b, a Wnt signaling inhibitor, were both decreased in p75, TROY, and Nogo-C2/NgRH1a morphants; moreover, dkk1b mRNA injection could rescue the defects in neuromast formation resulting from knockdown of p75 or TROY. We thus suggest that a novel Nogo-C2 complex, consisting of Nogo-C2, NgRH1a, p75, and TROY, regulates Fgf signaling and dkk1b expression, thereby ensuring stable organization of the PLL primordium. Show less

Myelination and neurite outgrowth both occur during brain development, and their disturbance has been previously been implicated in the pathophysiology of schizophrenia. Leucine-rich repeat and immunoglobulin domain-containing protein (Lingo-1) is a potent negative regulator of axonal myelination and neurite extension. As co-factors of Lingo-1 signaling (Nogo receptor (NgR), With No Lysine (K) (WNK1) and Myelin transcription factor 1 (Myt1)) have been implicated in the genetics of schizophrenia, we explored for the first time the role of Lingo-1 signaling pathways in this disorder. Lingo-1 protein, together with its co-receptor and co-factor proteins NgR, tumor necrosis factor (TNF) receptor orphan Y (TROY), p75, WNK1 and Myt1, have never been explored in the pathogenesis of schizophrenia. We examined protein levels of Lingo-1, NgR, TROY, p75, WNK1, Myt1 and myelin basic protein (MBP) (as a marker of myelination) within the post-mortem dorsolateral prefrontal cortex (DLPFC) (37 schizophrenia patients versus 37 matched controls) and hippocampus (Cornu Ammonis, CA1 and CA3) (20 schizophrenia patients versus 20 matched controls from the same cohort). Both of these brain regions are highly disrupted in the schizophrenia pathophysiology. There were significant increases in Lingo-1 (P<0.001) and Myt1 (P=0.023) and a reduction in NgR (P<0.001) in the DLPFC in schizophrenia subjects compared with controls. There were also increases in both TROY (P=0.001) and WNK1 (P=0.011) in the CA1 of schizophrenia subjects and, in contrast to the DLPFC, there was an increase in NgR (P=0.006) in the CA3 of schizophrenia subjects compared with controls. No significant difference was reported for MBP levels (P>0.05) between the schizophrenia and control groups in the three tested regions. This is the first time that a study has shown altered Lingo-1 signaling in the schizophrenia brain. Our novel findings may present a direct application for the use of a Lingo-1 antagonist to complement current and future schizophrenia therapies. Show less

Obesity is often associated with the development of cardiac hypertrophy but the hypertrophy-related pathways in obesity remain unknown. The purpose of this study was to evaluate cardiac hypertrophy-related markers, atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), tumor necrosis factor-alpha (TNFα) and hypertrophy-related pathways, interleukin (IL)-6-STAT3, IL-6-MEK5-ERK5 and calcineurin-nuclear factor of activated T-cells (NFAT)3 in the excised hearts from obese rats. Twelve obese Zucker rats were studied at 5-6 months of age and twelve age-matched lean Zucker rats served as the control group. The cardiac characteristics, myocardial architecture, ANP, BNP, TNFα levels, IL-6, STAT3, p-STAT3, MEK5, ERK-5, p-ERK-5, calcineurin and NFAT3 in the left ventricle from the rats were measured by heart weight index, echocardiography, vertical cross section, histological analysis, reverse transcription polymerase chain reaction and western blotting. Compared with the lean control, the whole heart weight, the left ventricule weight, the ratio of the whole heart weight to tibia length, echocardiographic interventricular septum, left ventricular posterior wall thickness, myocardial morphological changes and systolic blood pressure were found to increase in the obese rats. The protein levels of ANP, BNP, TNFα, IL-6, STAT3, p-STAT3, MEK-5, ERK-5, p-ERK 5, calcineurin and NFAT3 were also significantly increased in the hearts of the obese rats. The results showed that the hypertrophy-related markers, ANP, BNP and TNFα, the hypertrophy-related pathways IL-6-STAT3 and IL-6-MEK5-ERK5, and the calcineurin-NFAT3 hypertrophy-related pathways were more active in obese Zucker rats, which may provide possible hypertrophic mechanisms for developing cardiac hypertrophy and pathological changes in obesity. Show less

To explore the effects of serum insulin on the expression of ChREBP, ACC and FAS in vivo, KKAy mice which were characterized with high levels of both serum insulin and glucose and DIO mice which were characterized with high serum insulin level alone were utilized, separately. The age-matched C57BL/6J mice fed with standard chow were used as normal control (Con). Expressions of hepatic ChREBP, ACC and FAS were detected by Western blotting. As the results, in KKAy mice, a positive correlation between the levels of serum insulin and glucose (r = 0.902, P < 0.000), as well as between the levels of serum insulin and TG (r = 0.732, P < 0.000), was observed. Meanwhile, the expressions of hepatic ChREBP, ACC and FAS increased significantly and accompanied with its hyperinsulinemia and hyperglycemia, separately. In DIO mice, correlation between the levels of serum insulin and TG (r = 0.722, P < 0.001) also showed positive, and the expressions of hepatic ChREBP, ACC and FAS increased significantly and also accompanied with its hyperinsulinemia. However, their blood glucose values were almost normal. These demonstrated that hyperinsulinemia may cause glycolipid metabolic disorders by up-regulating the expression of ChREBP in vivo. Show less

This study was designed to investigate the direct effects of fatty acids (FAs) on the cell viability and the expression levels of genes involved in lipid metabolism in LO2 human liver cells. Palmitate (PA), oleate (OA) and docosahaexenoic acid (DHA) were used to represent saturated, mono-unsaturated and polyunsaturated FAs, respectively. At concentrations of ≤3.2 µg/ml, treatment with single FAs increased the viability of the LO2 cells. At FA concentrations of >3.2 µg/ml, cell viability following OA treatment was increased, but PA or DHA treatment at these concentrations reduced cell viability. Administration of mixtures of these FAs in three ratios (PA:OA:DHA = 1:2:1, 1:1:1 and 1:1:2, respectively) increased the cell viability compared with the control group. The intracellular triglyceride (TG) levels following all types of treatment were significantly increased and the accumulation of TGs was markedly increased with high doses of DHA. In addition, peroxisome proliferator-activated receptor-γ was significantly upregulated in all groups, with the exception of the 1:1:1 group at 3.2 µg/ml and the 1:1:2 group at 12.8 µg/ml. The expression levels of sterol regulatory-element binding protein‑1c, liver X receptor α and apolipoprotein C‑I were significantly reduced in all groups with the exception of the DHA‑treated group and the 1:2:1 groups at 3.2 and 12.8 µg/ml. In conclusion, these results indicate that the type, concentration and mixture ratios of FAs are all important in determining the cell viability and lipid metabolism-related gene expression in LO2 hepatocytes. Show less

The nuclear receptor liver X receptor (LXR) plays an important role in the metabolism and homeostasis of cholesterol, lipids, bile acids, and steroid hormones. In this study, we uncovered a function of LXRα (NR1H3) in regulating the human hydroxysteroid sulfotransferase SULT2A1, a phase II conjugating enzyme known to sulfonate bile acids, hydroxysteroid dehydroepiandrosterone, and related androgens. We showed that activation of LXR induced the expression of SULT2A1 at mRNA, protein, and enzymatic levels. A combination of promoter reporter gene and chromatin immunoprecipitation assays showed that LXRα transactivated the SULT2A1 gene promoter through its specific binding to the -500- to -258-base pair region of the SULT2A1 gene promoter. LXR small interfering RNA knockdown experiments suggested that LXRα, but not LXRβ, played a dominant role in regulating SULT2A1. In primary human hepatocytes, we found a positive correlation between the expression of SULT2A1 and LXRα, which further supported the regulation of SULT2A1 by LXRα. In summary, our results established human SULT2A1 as a novel LXRα target gene. The expression of LXRα is a potential predictor for the expression of SULT2A1 in human liver. Show less

Vascular endothelial injury is a major cause of many cardiovascular diseases. The proliferation and migration of endothelial progenitor cells (EPCs) play a pivotal role in endothelial regeneration and repair after vascular injury. Recently, liver X receptor (LXR) activation has been suggested as a potential target for novel therapeutic interventions in the treatment of cardiovascular disease. However, the effects of LXR activation on endothelial regeneration and repair, as well as EPC function, have not been investigated. In the present study, we demonstrate that LXRs, including LXRα and LXRβ, are expressed and functional in rat bone marrow-derived EPCs. Treatment with an LXR agonist, TO901317 (TO) or GW3965 (GW), significantly increased the proliferation and migration of EPCs, as well as Akt and eNOS phosphorylation in EPCs. Moreover, LXR agonist treatment enhanced the expression and secretion of vascular endothelial growth factor in EPCs. LXR agonists accelerated re-endothelialization in injured mouse carotid arteries in vivo. These data confirm that LXR activation may improve EPC function and endothelial regeneration and repair after vascular injury by activating the PI3K/Akt/eNOS pathway. We conclude that LXRs may be attractive targets for drug development in the treatment of cardiovascular diseases associated with vascular injury. Show less

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

Liver X receptors (LXRs), including LXRα and LXRβ isoforms, have important roles in the metabolic regulation of glucose, cholesterol and lipid. Moreover, activation of LXRs also represses the expression of cyclin D1 and cyclin B1, and thus suppresses the proliferation of multiple cancer cells, but the relevant mechanism is not well known. Forkhead box M1 (FOXM1) is a proliferation-specific member of forkhead box family, which is highly expressed in proliferating normal cells and numerous cancer cells. FOXM1 directly activates transcription of cyclin D1 and cyclin B1, resulting in the enhancement of cell cycle progression and cell proliferation. However, it is unclear whether LXRs are involved in the regulation of FOXM1. In this study, we demonstrated that specific LXRs agonists downregulated expression of FOXM1, cyclin D1 and cyclin B1 in hepatocellular carcinoma (HCC) cells, which led to cell cycle and cell proliferation arrest. Knockdown of FOXM1 significantly alleviated LXRs activation-mediated cell cycle arrest and cell growth suppression. Reporter assays showed that the activation of LXRs significantly reduced the transcriptional activity of FOXM1 promoter. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays demonstrated that LXRα but not LXRβ could bind to an inverted repeat IR2 (-52CCGTCAcgTGACCT-39) in the promoter region of FOXM1 gene. Moreover, the xenograft tumor growth and the corresponding FOXM1 expression in nude mice were dramatically repressed by LXRs agonists. Taken together, we conclude that LXRα but not LXRβ functions as a transcriptional repressor for FOXM1 expression. The pathway 'LXRα-FOXM1-cyclin D1/cyclin B1' is a novel mechanism by which LXRs suppress the proliferation of HCC cells, suggesting that the pathway may be a novel target for HCC treatment. Show less

Identification of genetic variants that influence bipolar I disorder (BPD-I) through genome-wide association (GWA) studies is limited in Asian populations. The current study aimed to identify novel common variants for BPD-I in an ethnically homogeneous Taiwanese sample using a multi-stage GWA study design. At the discovery stage, 200 BPD-I patients and 200 controls that combined to form 16 pools were genotyped with 1 million markers. Utilizing a newly developed rank-based method, top-ranked markers were selected. After validation with individual genotyping, a fine-mapping association study was conducted to identify associated loci using 240 patients and 240 controls. At the last stage, independent samples were collected (351 cases and 341 controls) for replication. Among the top-ranked markers from the discovery stage, eight genes and 15 individual SNPs were evaluated in the fine-mapping stage. At this stage, rs7619173, which is not in a gene coding region, showed the most significant association (P = 2 ∗ 10(-5)) with BPD-I. Four genes had empirical P-values<0.05, including KCNH7 (P = 0.0047), MYST4 (P = 0.0047), NRXN3 (P = 0.0095), and SEMA3D (P = 0.037). For markers genotyped in replication samples, rs7619173 exhibited a significant association (P(combined) = 2 ∗ 10(-4)) after multiple testing correction, while markers rs11001178 (MYST4) and rs2217887 (NRXN3) showed weak associations (P(combined) = 0.02) with BPD-I. A multi-stage GWA design has the potential to uncover the underlying pathogenesis of a complex trait. Findings in the present study highlight three loci that warrant further investigation for bipolar. Show less

Autophagy, a "self-eating" cellular process, has dual roles in promoting and suppressing tumor growth, depending on cellular context. PTP4A3/PRL-3, a plasma membrane and endosomal phosphatase, promotes multiple oncogenic processes including cell proliferation, invasion, and cancer metastasis. In this study, we demonstrate that PTP4A3 accumulates in autophagosomes upon inhibition of autophagic degradation. Expression of PTP4A3 enhances PIK3C3-BECN1-dependent autophagosome formation and accelerates LC3-I to LC3-II conversion in an ATG5-dependent manner. PTP4A3 overexpression also enhances the degradation of SQSTM1, a key autophagy substrate. These functions of PTP4A3 are dependent on its catalytic activity and prenylation-dependent membrane association. These results suggest that PTP4A3 functions to promote canonical autophagy flux. Unexpectedly, following autophagy activation, PTP4A3 serves as a novel autophagic substrate, thereby establishing a negative feedback-loop that may be required to fine-tune autophagy activity. Functionally, PTP4A3 utilizes the autophagy pathway to promote cell growth, concomitant with the activation of AKT. Clinically, from the largest ovarian cancer data set (GSE 9899, n = 285) available in GEO, high levels of expression of both PTP4A3 and autophagy genes significantly predict poor prognosis of ovarian cancer patients. These studies reveal a critical role of autophagy in PTP4A3-driven cancer progression, suggesting that autophagy could be a potential Achilles heel to block PTP4A3-mediated tumor progression in stratified patients with high expression of both PTP4A3 and autophagy genes. Show less

WASH (Wiskott-Aldrich syndrome protein (WASP) and SCAR homolog) was identified to function in endosomal sorting via Arp2/3 activation. We previously demonstrated that WASH is a new interactor of BECN1 and present in the BECN1-PIK3C3 complex with AMBRA1. The AMBRA1-DDB1-CUL4A complex is an E3 ligase for K63-linked ubiquitination of BECN1, which is required for starvation-induced autophagy. WASH suppresses autophagy by inhibition of BECN1 ubiquitination. However, how AMBRA1 is regulated during autophagy remains elusive. Here, we found that RNF2 associates with AMBRA1 to act as an E3 ligase to ubiquitinate AMBRA1 via K48 linkage. RNF2 mediates ubiquitination of AMBRA1 at lysine 45. Notably, RNF2 deficiency enhances autophagy induction. Upon autophagy induction, RNF2 potentiates AMBRA1 degradation with the help of WASH. WASH deficiency impairs the association of RNF2 with AMBRA1 to impede AMBRA1 degradation. Our findings reveal another novel layer of regulation of autophagy through WASH recruitment of RNF2 for AMBRA1 degradation leading to downregulation of autophagy. Show less

The miR-183/-96/-182 cluster is a conserved polycistronic microRNA (miRNA) cluster which is highly expressed in most breast cancers. Although there are some sporadic reports which demonstrate the importance of each miRNA in this cluster in breast cancer, the biological roles of this cluster as a whole and its regulation mechanisms in breast cancer are still unclear. We compared the expression of this cluster in different cancer types, analyzed the regulation mechanism of this cluster, identified new target genes, and examined the impact of this cluster on breast cancer cells. The miRNA level was detected by LNA-based northern blot and Real-time PCR, and was also analyzed from TCGA dataset. Bioinformatics research and luciferase assay were applied to find the promoter regions and transcription factors. To investigate the biological effects of the miR-183/-96 /-182 cluster in breast cancer, we generated miR-96, miR-182 and miR-183 overexpression stable cell lines to check the overdose effects; we also used miR-Down™ antagomir for each miRNA as well as miR-183/-96 /-182 cluster sponge lentivirus to check the knockdown effects. Growth, migration, cell cycle profile and survival of these cells was then monitored by colony formation assay, MTT assay, cell wound healing assay, flow cytometry and microscopy. The target gene was validated by Real-time PCR, luciferase assay, Western blot and Phalloidin/DAPI counterstaining. The miR-183/-96/-182 cluster was highly expressed in most breast cancers, and its transcription is disordered in breast cancer. The miR-183/-96/-182 cluster was transcribed in the same pri-miRNA and its transcription was regulated by ZEB1 and HSF2. It increased breast cell growth by promoting more rapid completion of mitosis, promoted cell migration and was essential for cell survival. MiR-183 targeted the RAB21 mRNA directly in breast cancer. The miR-183/-96/-182 cluster is up-regulated in most breast cancer. It functions as an oncogene in breast cancer as it increases cell proliferation and migration. Show less

The goal of this study was to investigate the effect of octreotide on the expression of intestinal fat absorption-associated apolipoproteinB48 (apoB48), microsomal triglyceride transfer protein (MTP) and apolipoproteinAIV (apoAIV) in a high-fat diet-induced obesity rat model. Sprague-Dawley rats were placed into a control or high-fat diet group. Obese rats from the high-fat diet group were further divided into an obese group and an octreotide-treated group. Rats in the octreotide-treated group were subcutaneously injected with octreotide (40 μg/kg body weight) twice daily for 8 d. Body weight, fasting plasma glucose (FPG), fasting serum insulin, triglyceride (TG), total cholesterol (TC), and high density lipoprotein-cholesterol (HDL-C) were measured. Intestinal MTP, apoB48, and apoAIV expression levels were determined by real-time polymerase chain reaction, Western blot, or enzyme-linked immunosorbent assay analysis. We found high-fat diet-induced obesity rats express more apoB, MTP, and apoAIV mRNA as well as apoB48 and MTP protein in the intestine than normal chow-fed rats. This observation occurred along with increased body weight, FPG, TG, TC, fasting serum insulin, and Homeostatic Model Assessment value. Octreotide intervention significantly decreased body weight and blood parameters, and down-regulated expression of apoB mRNA and apoB48 protein, as well as MTP mRNA and proteins. However, apoAIV mRNA was not significantly different between obese and octreotide-treated rats although it was decreased by 47%. High-fat diet-induced obesity is associated with increased expression of apoB48, MTP, and apoAIV in the intestine. Octreotide intervention inhibited the overexpression of apoB48 and MTP, and consequently brought about reduced fat absorption and weight loss. Show less

The purpose of this study was to evaluate the relationship between apolipoprotein A-IV (apoA-IV) plasma concentrations and acute coronary syndrome (ACS). Plasma apoA-IV concentrations were measured in 115 patients with different types of ACS and in 68 gender- and age-matched control subjects using Enzyme-Linked Immunosorbent Assay (ELISA) kits. The clinical data were collected by an internist, who was blinded to plasma apoA-IV concentrations. Plasma apoA-IV levels in ACS patients were significantly decreased compared to the levels in control subjects (437.0±157.5 μg/mL vs. 590.2±183.7 μg/mL, P<0.001). An statistically significant decreasing trend of plasma apoA-IV levels from the control subjects, to patients with unstable angina pectoris (UAP) (457.3±152.9 μg/mL), to patients with acute myocardial infarction (AMI) (311.7±127.8 μg/mL), was observed. Moreover, plasma apoA-IV level was negatively associated with New York Heart Association (NYHA) functional class. NYHA class II (467.2±142.1 μg/mL, P<0.001) and class III/IV (368.1±170.8 μg/mL, P<0.001) patients had statistically decreased levels of plasma apoA-IV when compared to the control subjects. A stepwise multivariate regression analysis identified types of ACS, NYHA classes, and plasma fibrinogen levels as the most important determinants of plasma apoA-IV levels in ACS patients. Low plasma apoA-IV levels are associated with ACS, and plasma apoA-IV levels may be a potential treatment target for ACS patients. Show less

Statin-fibrate combination therapy has been used to treat patients with acute coronary syndrome (ACS) complicated by elevated triglycerides (TG) and decreased high density lipoprotein cholesterol (HDL-C). The purpose of this study was to evaluate the influence of the combination therapy on lipids profile and apolipoprotein A5 (apoA5) level in patients with ACS. One hundred and four patients with ACS were recruited and randomly assigned into two groups: one was statin group (n = 52), given atorvastatin (20 mg QN) or other statins with equivalent dosages; the other was combination group (n = 52), given the same dose of statin plus bezafibrate (200 mg BID). Follow-up visits were scheduled at the end of 6 and 12 weeks post treatment. Serum apoA5 levels were determined using a commercial available ELISA kit. (1) Compared with that of statin monotherapy, statin-bezafibrate combination treatment not only resulted in a significant reduction of TG, TC and LDL-C levels, (all p < 0.05), but also led to increases in HDL-C and apoA5 levels (p < 0.05).(2) The percentage changes of TC, TG, LDL-C and apoA5 levels in both groups were even bigger at 12 weeks after treatment than that at 6 weeks (all p < 0.05). Similarly, the rates of achieving lipid-control target were higher in statin-bezafibrate combination treatment group than those in statin monotherapy group (all p < 0.05).(3) Spearman rank correlation analysis showed that the pre-treatment apoA5 level was positively correlated with TG (r = 0.359, p = 0.009). However, a negative correlation was observed between apoA5 and TG (r = -0.329, p = 0.017) after 12 weeks treatment. Statin and fibrate combination therapy is more effective than statin alone in achieving a comprehensive lipid control for ACS patients. Serum apoA5 elevation after statin and fibrate combination treatment could be due to the synergistic effect of both drugs on hypertriglyceridemia control. 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

The goal of our study is to investigate the combined contribution of 10 genetic variants to diabetes susceptibility. Bibliographic databases were searched from 1970 to Dec 2012 for studies that reported on genetic association study of diabetes. After a comprehensive filtering procedure, 10 candidate gene variants with informative genotype information were collected for the current meta-anlayses. Using the REVMAN software, odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the combined contribution of the selected genetic variants to diabetes. A total of 37 articles among 37,033 cases and 54,716 controls were involved in the present meta-analyses of 10 genetic variants. Three variants were found to be significantly associated with type 1 diabetes (T1D): NLRP1 rs12150220 (OR = 0.71, 95% CI = 0.55-0.92, P = 0.01), IL2RA rs11594656 (OR = 0.86, 95% CI = 0.82-0.91, P<0.00001), and CLEC16A rs725613 (OR = 0.71, 95% CI = 0.55-0.92, P = 0.01). APOA5 -1131T/C polymorphism was shown to be significantly associated with of type 2 diabetes (T2D, OR = 1.27, 95% CI = 1.03-1.57, P = 0.03). No association with diabetes was showed in the meta-analyses of other six genetic variants, including SLC2A10 rs2335491, ATF6 rs2070150, KLF11 rs35927125, CASQ1 rs2275703, GNB3 C825T, and IL12B 1188A/C. Our results demonstrated that IL2RA rs11594656 and CLEC16A rs725613 are protective factors of T1D, while NLRP1 rs12150220 and APOA5 -1131T/C are risky factors of T1D and T2D, respectively. Show less

α-Thalassemia is an inherited autosomal recessive disorder. It is one of the most common monogenic abnormalities known in the world and is prevalent in tropical and subtropical regions. α-Thalassemia is more frequently caused by deletional type than non-deletional type. Recently, we identified a novel large deletional type of α-thalassemia named --(FZ)/αα from a family in South China. Multiplex ligation-dependent probe amplification was used for diagnosing the carrier and prenatal diagnosing for a fetus. Real-time PCR was employed for characterizing the deletion breakpoints and the deletional segment was determined as 300 kb in length extending from the telomere to AXIN1 gene on the short arm of chromosome 16. The carriers in the family members were detected by real-time PCR using designed primers. 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

Plasma lipid levels are important risk factors for cardiovascular disease and are influenced by genetic and environmental factors. Recent genome wide association studies (GWAS) have identified several lipid-associated loci, but these loci have been identified primarily in European populations. In order to identify genetic markers for lipid levels in a Chinese population and analyze the heterogeneity between Europeans and Asians, especially Chinese, we performed a meta-analysis of two genome wide association studies on four common lipid traits including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL) and high-density lipoprotein cholesterol (HDL) in a Han Chinese population totaling 3,451 healthy subjects. Replication was performed in an additional 8,830 subjects of Han Chinese ethnicity. We replicated eight loci associated with lipid levels previously reported in a European population. The loci genome wide significantly associated with TC were near DOCK7, HMGCR and ABO; those genome wide significantly associated with TG were near APOA1/C3/A4/A5 and LPL; those genome wide significantly associated with LDL were near HMGCR, ABO and TOMM40; and those genome wide significantly associated with HDL were near LPL, LIPC and CETP. In addition, an additive genotype score of eight SNPs representing the eight loci that were found to be associated with lipid levels was associated with higher TC, TG and LDL levels (P = 5.52 × 10(-16), 1.38 × 10(-6) and 5.59 × 10(-9), respectively). These findings suggest the cumulative effects of multiple genetic loci on plasma lipid levels. Comparisons with previous GWAS of lipids highlight heterogeneity in allele frequency and in effect size for some loci between Chinese and European populations. The results from our GWAS provided comprehensive and convincing evidence of the genetic determinants of plasma lipid levels in a Chinese population. Show less

Protein activities controlled by receptor protein tyrosine phosphatases (RPTPs) play comparably important roles in transducing cell surface signals into the cytoplasm by protein tyrosine kinases. Previous studies showed that several RPTPs are involved in neuronal generation, migration, and axon guidance in Drosophila, and the vertebrate hippocampus, retina, and developing limbs. However, whether the protein tyrosine phosphatase type O (ptpro), one kind of RPTP, participates in regulating vertebrate brain development is largely unknown. We isolated the zebrafish ptpro gene and found that its transcripts are primarily expressed in the embryonic and adult central nervous system. Depletion of zebrafish embryonic Ptpro by antisense morpholino oligonucleotide knockdown resulted in prominent defects in the forebrain and cerebellum, and the injected larvae died on the 4th day post-fertilization (dpf). We further investigated the function of ptpro in cerebellar development and found that the expression of ephrin-A5b (efnA5b), a Fgf signaling induced cerebellum patterning factor, was decreased while the expression of dusp6, a negative-feedback gene of Fgf signaling in the midbrain-hindbrain boundary region, was notably induced in ptpro morphants. Further analyses demonstrated that cerebellar defects of ptpro morphants were partially rescued by inhibiting Fgf signaling. Moreover, Ptpro physically interacted with the Fgf receptor 1a (Fgfr1a) and dephosphorylated Fgfr1a in a dose-dependant manner. Therefore, our findings demonstrate that Ptpro activity is required for patterning the zebrafish embryonic brain. Specifically, Ptpro regulates cerebellar formation during zebrafish development through modulating Fgf signaling. Show less

To identify the genetic cause for a Chinese Han family affected with hereditary multiple osteochondromas. Two patients, five unaffected relatives of the family and 100 unrelated healthy controls were collected. The coding sequences and intron/exon boundaries of EXT1 gene were amplified with polymerase chain reaction (PCR) and sequenced. A heterozygous c.600G>A (p.Trp200X) mutation in exon 1 of the EXT1 gene was detected in the patients. The same mutation was not found in unaffected family members and 100 healthy controls. The hereditary multiple osteochondromas in the family is caused by a nonsense mutation (p.Trp200X) in the EXT1 gene. Show less

The exostosin (EXT) genes encode glycosyltransferases required for glycosaminoglycan chain polymerization in the biosynthesis of heparan sulfate proteoglycans (HSPGs). Mutations in the tumor suppressor genes EXT1 and EXT2 disturb HSPG biosynthesis and cause multiple osteochondroma (MO). How EXT1 and EXT2 traffic within the Golgi complex is not clear. Here, we show that Rotini (Rti), the Drosophila GOLPH3, regulates the retrograde trafficking of EXTs. A reduction in Rti shifts the steady-state distribution of EXTs to the trans-Golgi. These accumulated EXTs tend to be degraded and their re-entrance towards the route for polymerizing GAG chains is disengaged. Conversely, EXTs are mislocalized towards the transitional endoplasmic reticulum/cis-Golgi when Rti is overexpressed. Both loss of function and overexpression of rti result in incomplete HSPGs and perturb Hedgehog signaling. Consistent with Drosophila, GOLPH3 modulates the dynamic retention and protein stability of EXT1/2 in mammalian species. Our data demonstrate that GOLPH3 modulates the activities of EXTs, thus implicating a putative role for GOLPH3 in the formation of MO. Show less

The Notch signaling is an evolutionarily conserved cell-cell communication pathway that plays critical roles in the proliferation, survival, apoptosis, and fate determination of mammalian cells. Retinal pigment epithelial (RPE) cells are responsible for supporting the function of the neural retina and maintaining vision. This study investigated the function of Notch signaling in RPE cells. We found that the members of the Notch signaling pathway components were differentially expressed in RPE cells. Furthermore, blockage of Notch signaling inhibited the migration and proliferation of RPE cells and reduced the expression levels of certain Notch signaling target genes, including HES1, MYC, HEY2, and SOX9. Our data reveal a critical role of Notch signaling in RPE cells, suggesting that targeting Notch signaling may provide a novel approach for the treatment of ophthalmic diseases related to RPE cells. Show less

The mature aortic valve is composed of a structured trilaminar extracellular matrix that is interspersed with aortic valve interstitial cells (AVICs) and covered by endothelium. Dysfunction of the valvular endothelium initiates calcification of neighboring AVICs leading to calcific aortic valve disease (CAVD). The molecular mechanism by which endothelial cells communicate with AVICs and cause disease is not well understood. Using a co-culture assay, we show that endothelial cells secrete a signal to inhibit calcification of AVICs. Gain or loss of nitric oxide (NO) prevents or accelerates calcification of AVICs, respectively, suggesting that the endothelial cell-derived signal is NO. Overexpression of Notch1, which is genetically linked to human CAVD, retards the calcification of AVICs that occurs with NO inhibition. In AVICs, NO regulates the expression of Hey1, a downstream target of Notch1, and alters nuclear localization of Notch1 intracellular domain. Finally, Notch1 and NOS3 (endothelial NO synthase) display an in vivo genetic interaction critical for proper valve morphogenesis and the development of aortic valve disease. Our data suggests that endothelial cell-derived NO is a regulator of Notch1 signaling in AVICs in the development of the aortic valve and adult aortic valve disease. Show less