👤 Ying Chi

Recurrent breast cancer presents significant challenges with aggressive phenotypes and treatment resistance. Therefore, novel therapeutics are urgently needed. Here, we report that murine recurrent breast tumor cells, when compared with primary tumor cells, are highly sensitive to ferroptosis. Discoidin Domain Receptor Tyrosine Kinase 2 (DDR2), the receptor for collagen I, is highly expressed in ferroptosis-sensitive recurrent tumor cells and human mesenchymal breast cancer cells. EMT regulators, TWIST and SNAIL, significantly induce DDR2 expression and sensitize ferroptosis in a DDR2-dependent manner. Erastin treatment induces DDR2 upregulation and phosphorylation, independent of collagen I. Furthermore, DDR2 knockdown in recurrent tumor cells reduces clonogenic proliferation. Importantly, both the ferroptosis protection and reduced clonogenic growth may be compatible with the compromised YAP/TAZ upon DDR2 inhibition. Collectively, these findings identify the important role of EMT-driven DDR2 upregulation in recurrent tumors in maintaining growth advantage but activating YAP/TAZ-mediated ferroptosis susceptibility, providing potential strategies to eradicate recurrent breast cancer cells with mesenchymal features. Show less

Ferroptosis is a novel form of programmed cell death. We found that the ferroptosis sensitivity in renal and ovarian cancers are regulated by cell density through TAZ-EMP1-NOX4 and TAZ-ANGPTL4-NOX2 pathway, respectively. These findings reveal TAZ as a novel genetic determinant of ferroptosis. Triggering ferroptosis may have therapeutic potential for TAZ-activated tumors. Show less

Ovarian cancer is the deadliest gynecologic cancer. Despite recent advances, clinical outcomes remain poor, necessitating novel therapeutic approaches. To investigate metabolic susceptibility, we performed nutrigenetic screens on a panel of clear cell and serous ovarian cancer cells and identified cystine addiction and vulnerability to ferroptosis, a novel form of regulated cell death. Our results may have therapeutic potential, but little is known about the determinants of ferroptosis susceptibility in ovarian cancer. We found that vulnerability to ferroptosis in ovarian cancer cells is enhanced by lower cell confluency. Because the Hippo pathway effectors Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) are recognized as sensors of cell density, and TAZ is the predominant effector in the tested ovarian cancer cell lines, we investigated the role of TAZ in ferroptosis of ovarian cancer. TAZ removal confers ferroptosis resistance, while TAZS89A overexpression sensitizes cells to ferroptosis. In addition, we found that lower TAZ level in chemo-resistant recurrent ovarian cancer is responsible for reduced ferroptosis susceptibility. The integrative genomic analysis identified ANGPTL4 as a direct TAZ-regulated target gene that sensitizes ferroptosis by activating NOX2. Collectively, cell density-regulated ferroptosis in ovarian cancer is mediated by TAZ through the regulation of the ANGPTL4-NOX2 axis, suggesting therapeutic potentials for ovarian cancers and other TAZ-activated tumors. IMPLICATIONS: This study reveals that TAZ promotes ferroptosis in ovarian cancers by regulating ANGPTL4 and NOX, offering a novel therapeutic potential for ovarian tumors with TAZ activation. Show less

The aim of the present study is to investigate the role of RNA interference in the inhibition of MUC1 gene expression in occurrence and metastasis of oral squamous cell carcinoma (OSCC) and its in-depth mechanisms. The OSCC and normal oral mucosa tissues, as well as normal oral epithelial cell line HOK and OSCC cell line SCC-4, Cal-27, TSCCA, Tca8113 were obtained to detect the expression of MUC1. Slug expression in OSCC and normal oral mucosa tissues was also determined. The OSCC cells were grouped to investigate the role of MUC1 gene silencing on proliferation, DNA replication, cell cycle distribution, apoptosis, colony formation ability, epithelial-mesenchymal transition (EMT), invasion, and migration of OSCC cells. We first found higher positive rate of MUC1 and Slug expression in OSCC tissues. Next, it was determined that higher expression of MUC1 was found in OSCC tissues and cells. Furthermore, silencing of MUC1 declined Slug expression, inhibited the proliferation, DNA replication, cell cycle progression, and EMT while inducing apoptosis of OSCC cells. Our study suggests that overexpression of MUC1 is found in OSCC, and MUC1 gene silencing could inhibit the proliferation, invasion, and migration while inducing apoptosis of OSCC cells. Show less

Mice lacking glycosylphosphatidylinositol-anchored HDL-binding protein 1 (GPIHBP1) are unable to traffic LPL to the vascular lumen. Thus, triglyceride (TG) clearance is severely blunted, and mice are extremely hypertriglyceridemic. Paradoxically, mice lacking both GPIHBP1 and the LPL regulator, angiopoietin-like 4 (ANGPTL4), are far less hypertriglyceridemic. We sought to determine the mechanism by which Show less

Urothelial carcinoma (UC) carcinogenesis has been hypothesized to occur through epigenetic repression of tumor-suppressor genes (TSGs). By quantitative real-time polymerase chain reaction array, we found that one potential TSG, angiopoietin-like 4 (ANGPTL4), was expressed at very low levels in all bladder cancer cell lines we examined. Previous studies had demonstrated that ANGPTL4 is highly expressed in some cancers, but downregulated, by DNA methylation, in others. Consequently, owing to these seemingly conflicting functions in distinct cancers, the precise role of ANGPTL4 in the etiology of UC remains unclear. In this study, using methylation-specific PCR and bisulfite pyrosequencing, we show that ANGPTL4 is transcriptionally repressed by DNA methylation in UC cell lines and primary tumor samples, as compared with adjacent noncancerous bladder epithelium. Functional studies further demonstrated that ectopic expression of ANGPTL4 potently suppressed UC cell proliferation, monolayer colony formation in vitro, and invasion, migration, and xenograft formation in vivo. Surprisingly, circulating ANGPTL4 was significantly higher in plasma samples from UC patients than normal control, suggesting it might be secreted from other cell types. Interestingly, our data also indicated that exogenous cANGPTL4 could promote cell proliferation and cell migration via activation of signaling through the Erk/focal adhesion kinase axis. We further confirmed that mouse xenograft tumor growth could be promoted by administration of exogenous cANGPTL4. Finally, immunohistochemistry demonstrated that ANGPTL4 was downregulated in tumor cells but overexpressed in tumor adjacent stromal tissues of muscle-invasive UC tissue samples. In conclusion, our data support dual roles for ANGPTL4 in UC progression, either as a tumor suppressor or oncogene, in response to microenvironmental context. Show less

Angiopoietin-like 4 (ANGPTL4) is a fasting-induced inhibitor of lipoprotein lipase (LPL) and a regulator of plasma triglyceride metabolism. Here, we examined the kinetics of Gene expression, LPL activity, and triglyceride uptake were examined in fasted and fed wild-type and Show less

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

Angiotensin II (Ang II) is a major contributor to the development of heart failure. However, the molecular and cellular mechanisms that underlie this process remain elusive. Inadequate angiogenesis in the myocardium leads to a transition from cardiac hypertrophy to dysfunction, and our previous study showed that Ang II significantly impaired the angiogenesis response. The current study was designed to examine the role of Jagged1-Notch signaling in the effect of Ang II during impaired angiogenesis and cardiac hypertrophy. Ang II was subcutaneously infused into 8-week-old male C57BL/6 mice at a dose of 200 ng·kg-1·min-1 for 2 weeks using Alzet micro-osmotic pumps. N-[N-(3, 5-difluorophenacetyl)-L-alanyl]-S-phenylglycine tert-butyl ester (DAPT), a γ-secretase inhibitor, was injected subcutaneously during Ang II infusion at a dose of 10.0 mg·kg-1·d-1. Forty mice were divided into four groups (n = 10 per group): control group; Ang II group, treated with Ang II; DAPT group, treated with DAPT; and Ang II + DAPT group, treated with both Ang II and DAPT. At the end of experiments, myocardial (left ventricle [LV]) tissue from each experimental group was evaluated using immunohistochemistry, Western blotting, and real-time polymerase chain reaction. Data were analyzed using one-way analysis of variance test followed by the least significant difference method or independent samples t-test. Ang II treatment significantly induced cardiac hypertrophy and impaired the angiogenesis response compared to controls, as shown by hematoxylin and eosin (HE) staining and immunohistochemistry for CD31, a vascular marker (P < 0.05 for both). Meanwhile, Jagged1 protein was significantly increased, but gene expression for both Jag1 and Hey1 was decreased in the LV following Ang II treatment, compared to that in controls (relative ratio for Jag1 gene: 0.45 ± 0.13 vs. 0.84 ± 0.15; relative ratio for Hey1 gene: 0.51 ± 0.08 vs. 0.91 ± 0.09; P < 0.05). All these cellular and molecular effects induced by Ang II in the hearts of mice were reduced by DAPT treatment. Interestingly, Ang II stimulated Hey1, a known Notch target, but did not affect the expression of Hey2, another Notch target gene. A Jagged1-Hey1 signal might mediate the impairment of angiogenesis induced by Ang II during cardiac hypertrophy. Show less

Involvement of the RGS17 oncogene in the promotion of non-small-cell lung cancer (NSCLC) has been reported, but the regulation mechanism in NSCLC remains unclear. MicroRNAs (miRNAs) negatively regulate gene expression, and their dysregulation has been implicated in tumorigenesis. To understand the role of miRNAs in Regulator of G Protein Signaling 17 (RGS17)-induced NSCLC, we showed that miR-203 was downregulated during tumorigenesis, and inhibited the proliferation and invasion of lung cancer cells. We then determined whether miR-203 regulated NSCLC by targeting RGS17. To characterize the regulatory effect of miR-203 on RGS17, we used lung cancer cell lines, A549 and Calu-1, and the constructed miR-203 and RGS17 overexpression vectors. The CCK8 kit was used to determine cell proliferation, and the Transwell® assay was used to measure cell invasion and migration. RT-PCR, western blots, and immunofluorescence were used to analyze expression of miR-203 and RGS17, and the luciferase reporter assay was used to examine the interaction between miR-203 and RGS17. Nude mice were used to characterize in vivo tumor growth regulation. Expression of miR-203 inhibited proliferation, invasion, and migration of lung cancer cell lines A549 and Calu-1 by targeting RGS17. The regulatory effect of miR-203 was inhibited after overexpression of RGS17. The luciferase reporter assay showed that miR-203 downregulated RGS17 by direct integration into the 3'-UTR of RGS17 mRNA. In vivo studies showed that expression of miR-203 significantly inhibited growth of tumors. Taken together, the results suggested that expression of miR-203 inhibited tumor growth and metastasis by targeting RGS17. Show less

The Wnt signaling pathway plays a key role in many biological aspects, such as cellular proliferation, tissue regeneration, embryonic development, and other systemic effects. Under a physiological condition, it is tightly controlled at different layers and arrays, and a dysregulated activation of this signaling has been implicated into the pathogenesis of various human disorders, including autoimmune diseases. Despite the fact that therapeutic interventions are available for ameliorating disease manifestations, there is no curative therapy currently available for autoimmune disorders. Increasing lines of evidence have suggested a crucial role of Wnt signaling during the pathogenesis of many autoimmune diseases; in addition, some of microRNAs (miRNAs), a class of small, noncoding RNA molecules capable of transcriptionally regulating gene expression, have also recently been demonstrated to possess both physiological and pathological roles in autoimmune diseases by regulating the Wnt signaling pathway. This review summarizes currently our understanding of the pathogenic roles of Wnt signaling in several major autoimmune disorders and miRNAs, those targeting Wnt signaling in autoimmune diseases, with a focus on the implication of the Wnt signaling as potential biomarkers and therapeutic targets in immune diseases, as well as miRNA-mediated regulation of Wnt signaling activation in the development of autoimmune diseases. Show less

Brown fat has been highlight as a new therapeutic target for treatment of obesity and diabetes. However, molecular mechanism underlying brown adipogenesis are not fully understood. Here, we identified that MAP kinase phosphatase 3 (MKP3) has a novel role as regulator of brown adipocyte differentiation. The expression of MKP3 was significantly decreased during the early stage(s) of brown adipocyte differentiation in HIB-1B cells and primary cells. Ectopic expression of MKP3 led to reduced brown adipocyte differentiation, whereas depletion of MKP3 significantly enhanced the differentiation of primary brown preadipocytes. Consistently, we found an increased brown adipocyte differentiation in MKP3-null MEF cells. These inhibitory effects of MKP3 could be resulted via the temporal regulation of Erk activation. In recent, it was reported that MKP3 deficient mice are resistant to diet-induced obesity, and display enhanced energy expenditure. Taken together, we suggest that MKP3 could be an important factor in the regulation of brown adipocyte differentiation. Show less

Growth arrest is one of the essential features of cellular senescence. At present, the precise mechanisms responsible for the establishment of the senescence-associated arrested phenotype are still incompletely understood. Given that ERK1/2 is one of the major kinases controlling cell growth and proliferation, we examined the possible implication of ERK1/2. Exposure of normal rat epithelial cells to etoposide caused cellular senescence, as manifested by enlarged cell size, a flattened cell body, reduced cell proliferation, enhanced β-galactosidase activity, and elevated p53 and p21. Senescent cells displayed a blunted response to growth factor-induced cell proliferation, which was preceded by impaired ERK1/2 activation. Further analysis revealed that senescent cells expressed a significantly higher level of mitogen-activated protein phosphatase 3 (MKP-3, a cytosolic ERK1/2-targeted phosphatase), which was suppressed by blocking the transcriptional activity of the tumor suppressor p53 with pifithrin-α. Inhibition of MKP-3 activity with a specific inhibitor or siRNA enhanced basal ERK1/2 phosphorylation and promoted cell proliferation. Apart from its role in growth arrest, impairment of ERK1/2 also contributed to the resistance of senescent cells to oxidant-elicited cell injury. These results therefore indicate that p53-mediated up-regulation of MKP-3 contributes to the establishment of the senescent cellular phenotype through dephosphorylating ERK1/2. Impairment of ERK1/2 activation could be an important mechanism by which p53 controls cellular senescence. Show less

Metformin is used as a first-line oral treatment for type 2 diabetes (T2D). However, the underlying mechanism is not fully understood. Here, we aimed to comprehensively investigate the pleiotropic effects of metformin. We analyzed both metabolomic and genomic data of the population-based KORA cohort. To evaluate the effect of metformin treatment on metabolite concentrations, we quantified 131 metabolites in fasting serum samples and used multivariable linear regression models in three independent cross-sectional studies (n = 151 patients with T2D treated with metformin [mt-T2D]). Additionally, we used linear mixed-effect models to study the longitudinal KORA samples (n = 912) and performed mediation analyses to investigate the effects of metformin intake on blood lipid profiles. We combined genotyping data with the identified metformin-associated metabolites in KORA individuals (n = 1,809) and explored the underlying pathways. We found significantly lower (P < 5.0E-06) concentrations of three metabolites (acyl-alkyl phosphatidylcholines [PCs]) when comparing mt-T2D with four control groups who were not using glucose-lowering oral medication. These findings were controlled for conventional risk factors of T2D and replicated in two independent studies. Furthermore, we observed that the levels of these metabolites decreased significantly in patients after they started metformin treatment during 7 years' follow-up. The reduction of these metabolites was also associated with a lowered blood level of LDL cholesterol (LDL-C). Variations of these three metabolites were significantly associated with 17 genes (including FADS1 and FADS2) and controlled by AMPK, a metformin target. Our results indicate that metformin intake activates AMPK and consequently suppresses FADS, which leads to reduced levels of the three acyl-alkyl PCs and LDL-C. Our findings suggest potential beneficial effects of metformin in the prevention of cardiovascular disease. Show less

Genome-wide expression profiles reflect the transcriptional networks specific to the given cell context. However, most statistical models try to estimate the average connectivity of the networks from a collection of gene expression data, and are unable to characterize the context-specific transcriptional regulations. We propose an approach for mining context-specific transcription networks from a large collection of gene expression fold-change profiles and composite gene-set information. Using a composite gene-set analysis method, we combine the information of transcription factor binding sites, Gene Ontology or pathway gene sets and gene expression fold-change profiles for a variety of cell conditions. We then collected all the significant patterns and constructed a database of context-specific transcription networks for human (REGNET). As a result, context-specific roles of transcription factors as well as their functional targets are readily explored. To validate the approach, nine predicted targets of E2F1 in HeLa cells were tested using chromatin immunoprecipitation assay. Among them, five (Gadd45b, Dusp6, Mll5, Bmp2 and E2f3) were successfully bound by E2F1. c-JUN and the EMT transcription networks were also validated from literature. REGNET is a useful tool for exploring the ternary relationships among the transcription factors, their functional targets and the corresponding cell conditions. It is able to provide useful clues for novel cell-specific transcriptional regulations. The REGNET database is available at http://mgrc.kribb.re.kr/regnet. Show less

ATP binding cassette transporter A1 (ABCA1) is a member of the ATP-binding cassette transporter family. It plays an essential role in mediating the efflux of excess cholesterol. It is known that peroxisome proliferator-activated receptor gamma (PPARγ) promoted ABCA1 expression. We previously found 7-ketocholesteryl-9-carboxynonanoate (oxLig-1) upregulated ABCA1 partially through CD36 mediated signals. In the present study, we intended to test if PPARγ signally is involved in the upregulation mediated by oxLig-1. First, we docked oxLig-1 and the ligand-binding domain (LBD) of PPARγ by using AutoDock 3.05 and subsequently confirmed the binding by ELISA assay. Western blotting analyses showed that oxLig-1 induces liver X receptor alpha (LXRα), PPARγ and consequently ABCA1 expression. Furthermore, oxLig-1 significantly enhanced ApoA-I-mediated cholesterol efflux. Pretreatment with an inhibitor for PPARγ (GW9662) or/and LXRα (GGPP) attenuated oxLig-1-induced ABCA1 expression. Under PPARγ knockdown by using PPARγ-shRNA, oxLig-1-induced ABCA1 expression and cholesterol efflux in THP-1 macrophages was blocked by 62% and 25% respectively. These observations suggest that oxLig-1 is a novel PPARγ agonist, promoting ApoA-I-mediated cholesterol efflux from THP-1 macrophages by increasing ABCA1 expression via induction of PPARγ. Show less

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

Hemodialysis (HD) patients are under recurrent circulatory stress, and hemodialysis has a high mortality rate. The characteristics of plasma proteomes in patients surviving long-term HD remain obscure, as well as the potential biomarkers in predicting prognoses. This study reports the proteome analyses of patient plasma from non-diabetic long-term HD (LHD, dialysis vintage 14.9±4.1 years, n = 6) and the age/sex/uremic etiology-comparable short-term HD (SHD, dialysis vintage 5.3±2.9 years, n = 6) using 2-DE and mass spectrometry. In addition, a 4-year longitudinal follow-up of 60 non-diabetic HD patients was subsequently conducted to analyze the baseline plasma proteins by ELISA in predicting prognosis. Compared to the SHD, the LHD survivors had increased plasma vitamin D binding proteins (DBP) and decreased clusterin, apolipoprotein A-IV, haptoglobin, hemopexin, complement factors B and H, and altered isoforms of α1-antitrypsin and fibrinogen gamma. During the 45.7±15 months for follow-up of the 60 HD patient cases, 16 patients died. Kaplan-Meier analysis demonstrated that HD patients with the lowest tertile of the baseline plasma DBP level have a significantly higher mortality rate. Multivariate Cox regression analysis further indicated that DBP is an independent predictor of mortality. In summary, the altered plasma proteins in LHD implicated accelerated atherosclerosis, defective antioxidative activity, increased inflammation/infection, and organ dysfunction. Furthermore, lower baseline plasma DBP in HD patients is related to mortality. The results suggest that the proteomic approach could help discover the potential biomarker in HD prognoses. Show less

Multiplex reverse transcription polymerase chain reaction (mRT-PCR) has recently emerged as an alternative to cytogenetics. We designed and used simplified mRT-PCR system as a molecular screen for acute leukemia. Fifteen fusion transcripts were included: BCR-ABL1, PML-RARA, ZBTB16-RARA, RUNX1-RUNX1T1, CBFB-MYH11, DEK-NUP214, TCF3-PBX1, ETV6-RUNX1, MLL-AFF1, MLL-MLLT4, MLL-MLLT3, MLL-MLLT10, MLL-ELL, MLL-MLLT1, and MLL-MLLT6. A total of 121 diagnostic acute leukemia specimens were studied, comparing the mRT-PCR system with standard cytogenetics. Fifty-six cases (46.3%) had fusion transcripts revealed by our mRT-PCR assay. The concordance rate between mRT-PCR and cytogenetics was 91.7%. However, false negative results were found in three cases who have inv(16), t(4;11) or t(11;19)(q23;p13.1), respectively. Seven cryptic translocations including ETV6-RUNX1, MLL-MLLT3, MLL-MLLT4, and PML-RARA were detected. This mRT-PCR assay is a useful screening tool in acute leukemia because it provides rapid and reliable detection of clinically important chimeric transcripts. In addition, cryptic translocations provide additional genetic information that could be clinically useful. Show less

To investigate the gene expression profiles of adipose tissue of obese rats after central administration of neuropeptide Y-Y5 receptor antisense oligodeoxynucleotides (ODNs), Y5 receptor antisense, mismatched ODNs or vehicle was intracerebroventricularly injected and cDNA microarrays were undertaken. Central administration of NPY-Y5 receptor antisense ODNs decreased food intake, body weight and serum insulin compared with both vehicle and mismatched ODNs. The average area of adipocytes both at retroperitoneal and epididymal adipose tissue were fall in antisense group while only the weight of the retroperitoneal fat pats was reduced in antisense group. cDNA microarrays containing 18,000 genes/Ests were used to investigate gene expression of adipose tissue. Autoradiographic analysis showed that 404, 81, and 34 genes were differently expressed over twofold, threefold, and fivefold, respectively. The analysis of gene expression profiles indicated that 332 genes were up-regulated and 187 genes were down-regulated in response to Y5 receptor antisense ODNs treatment. Different clusters of genes associated with apoptosis, signal transduction, energy metabolism, lipid metabolism, etc., such as FXR1, PHLDA1, MAEA, PIK3R1, ICAM2, PITPN, CALM2, CAMK2D, PKIA, DRD2, SLC25A14, CKB, AADAC, LIPA, ACOX3, FADS1, were concerned. Analysis of differentially expressed genes will help to understand the effects of Y5 receptor antisense ODNs therapy. Show less

Multiple osteochondromatosis, also known as hereditary multiple exostoses (HME), is an inherited autosomal dominant disorder characterized by the presence of multiple exostoses on the long bones. These exostoses are benign cartilaginous tumors (enchondromata). Three different exostosis (EXT) loci on chromosomes 8q (exostosin 1, EXT1), 11p (exostosin 2, EXT2) and 19p (exostosin 3, EXT3) have been reported. Recently, the EXT1 and EXT2 genes were identified by positional cloning. Using polymerase chain reaction and direct sequencing, we analyzed the EXT1 and EXT2 genes in three familial cases and one sporadic case of HME in Taiwanese patients. We found three novel mutations (S277X in the EXT1 gene, and G194X and 939+1G>A in the EXT2 gene) and a known mutation (Q172X in the EXT2 gene). Mutation analysis in families with HME allows for genetic counseling and prenatal diagnosis. Show less

The vascular system is locally specialized to accommodate widely varying blood flow and pressure and the distinct needs of individual tissues. The endothelial cells (ECs) that line the lumens of blood and lymphatic vessels play an integral role in the regional specialization of vascular structure and physiology. However, our understanding of EC diversity is limited. To explore EC specialization on a global scale, we used DNA microarrays to determine the expression profile of 53 cultured ECs. We found that ECs from different blood vessels and microvascular ECs from different tissues have distinct and characteristic gene expression profiles. Pervasive differences in gene expression patterns distinguish the ECs of large vessels from microvascular ECs. We identified groups of genes characteristic of arterial and venous endothelium. Hey2, the human homologue of the zebrafish gene gridlock, was selectively expressed in arterial ECs and induced the expression of several arterial-specific genes. Several genes critical in the establishment of left/right asymmetry were expressed preferentially in venous ECs, suggesting coordination between vascular differentiation and body plan development. Tissue-specific expression patterns in different tissue microvascular ECs suggest they are distinct differentiated cell types that play roles in the local physiology of their respective organs and tissues. Show less

Tankyrase-1 and -2 are closely related poly(ADP-ribose) polymerases that use an ankyrin-repeat domain to bind diverse proteins, including TRF (telomere-repeat binding factor)-1, IRAP (insulin-responsive aminopeptidase), and TAB182 (182-kDa tankyrase-binding protein). TRF1 binding allows tankyrase to regulate telomere dynamics in human cells, whereas IRAP binding presumably allows tankyrase to regulate the targeting of IRAP. The mechanism by which tankyrase binds to diverse proteins has not been investigated. Herein we describe a novel RXXPDG motif shared by IRAP, TAB182, and human TRF1 that mediates their binding to tankyrases. Interestingly, mouse TRF1 lacks this motif and thus does not bind either tankyrase-1 or -2. Using the ankyrin domain of tankyrase as a bait in a yeast two-hybrid screen, we also found the RXXPDG motif in six candidate tankyrase partners, including the nuclear/mitotic apparatus protein (NuMA). We verified NuMA as an RXXPDG-mediated partner of tankyrase and suggest that this interaction contributes to the known colocalization of tankyrase and NuMA at mitotic spindle poles. Show less