Biomedical subjects

Ying Lin

Publications and source records attributed to Ying Lin.

At least 55 records · Page 3Linked to original sources

PubMed2003

COX-2-dependent stabilization of survivin in non-small cell lung cancer.

Elevated tumor cyclooxygenase 2 (COX-2) expression is associated with increased angiogenesis, tumor invasion and promotion of tumor cell resistance to apoptosis. The mechanism(s) by which COX-2 exerts its cytoprotective effects are not completely understood but may be due to an imbalance of pro- and anti-apoptotic gene expression. To analyze COX-2-dependent gene expression and apoptosis, we created cell lines constitutively expressing COX-2 cDNA in sense and antisense orientations. Whereas COX-2 sense cells have significantly heightened resistance to radiation and drug-induced apoptosis, COX-2 antisense cells are highly sensitive to apoptosis induction. We found that the expression of the anti-apoptotic protein survivin correlated positively with COX-2 expression. A COX-2-dependent modulation of survivin ubiquitination led to its stabilization in COX-2 overexpressing cells, and this effect was replicated by exogenous PGE2 treatment of parental tumor cells. In contrast to previous studies in other cell types, in nonsmall cell lung cancer cells survivin was expressed in a cell cycle-independent manner. When established in SCID mice in vivo, COX-2 antisense-derived tumors had significantly decreased survivin levels while COX-2 sense-derived tumors demonstrated elevated levels compared with controls. In accord with these findings, survivin and COX-2 were frequently upregulated and co-expressed in human lung cancers in situ.

Animals↗

PubMed2003

A transgenic mouse with a deletion in the collagenous domain of adiponectin displays elevated circulating adiponectin and improved insulin sensitivity.

Adiponectin is a plasma protein expressed exclusively in adipose tissue. Adiponectin levels are linked to insulin sensitivity, but a direct effect of chronically elevated adiponectin on improved insulin sensitivity has not yet been demonstrated. We identified a dominant mutation in the collagenous domain of adiponectin that elevated circulating adiponectin values in mice by 3-fold. Adiponectinemia raised lipid clearance and lipoprotein lipase activity, and suppressed insulin-mediated endogenous glucose production. The induction of adiponectin during puberty and the sexual dimorphism in adult adiponectin values were preserved in these transgenic animals. As a result of elevated adiponectin, serum PRL values and brown adipose mass both increased. The effects on carbohydrate and lipid metabolism were associated with elevated phosphorylation of 5'-AMP-activated protein kinase in liver and elevated expression of peroxisomal proliferator-activated receptor gamma2, caveolin-1, and mitochondrial markers in white adipose tissue. These studies strongly suggest that increasing endogenous adiponectin levels has direct effects on insulin sensitivity and may induce similar physiological responses as prolonged treatment with peroxisomal proliferator-activated receptor gamma agonists.

3T3-L1 Cells↗

PubMed2003

Ischemic insults derepress the gene silencer REST in neurons destined to die.

A subset of genes implicated in genetic and acquired neurological disorders encode proteins essential to neural patterning and neurogenesis. The gene silencing transcription factor neuronal repressor element-1 silencing transcription factor (REST)/neuron-restrictive silencer factor (NRSF) plays a critical role in elaboration of the neuronal phenotype. In neural progenitor and non-neural cells, REST acts by repression of a subset of neural genes important to synaptic plasticity and synaptic remodeling, including the AMPA receptor (AMPAR) subunit GluR2. Here we show that global ischemia triggers REST mRNA and protein expression. REST suppresses GluR2 promoter activity and gene expression in neurons destined to die. Because the GluR2 subunit governs AMPAR Ca2+ permeability, these changes are expected to have profound effects on neuronal survival. In keeping with this concept, acute knockdown of the REST gene by antisense administration prevents GluR2 suppression and rescues post-ischemic neurons from ischemia-induced cell death in an in vitro model. To our knowledge, our study represents the first example of ischemia-induced induction of a master transcriptional regulator gene and its protein expression critical to neural differentiation and patterning in adult neurons. Derepression of REST is likely to be an important mechanism of insult-induced neuronal death.

Animals↗

PubMed2003

Non-small cell lung cancer-derived soluble mediators enhance apoptosis in activated T lymphocytes through an I kappa B kinase-dependent mechanism.

T lymphocyte survival is critical for the development and maintenance of an effective host antitumor immune response; however, the tumor environment can negatively impact T-cell survival. Lymphocytes exposed to tumor supernatants (TSNs) were evaluated for apoptosis after mitogen stimulation. TSN was observed to significantly enhance phorbol 12-myristate 13-acetate/ionomycin- and anti-CD3-stimulated lymphocyte apoptosis. Enhanced lymphocyte apoptosis was associated with an impairment of nuclear factor kappa B nuclear translocation and diminished I kappa B alpha degradation. In lymphocytes stimulated after exposure to TSNs, cytoplasmic I kappa B alpha persisted as a result of alterations in I kappa B kinase (IKK) activity. Accordingly, although there were no apparent differences in IKK component concentrations, lymphocytes preexposed to TSNs exhibited markedly reduced IKK activity. We conclude that non-small cell lung cancer-derived soluble factors promote apoptosis in activated lymphocytes by an IKK-dependent pathway.

Adenocarcinoma↗

PubMed2003

Profiling of cytokine expression by biotin-labeled-based protein arrays.

Global analysis of protein expression holds great promise in basic research and patient care. Previously we demonstrated that multiple cytokines could be detected simultaneously using an enzyme-linked immunosorbent assay protein array system with high sensitivity and specificity. In this paper, we described a biotin-labeled-based protein array system to detect multiple cytokines simultaneously from biological samples. In this new approach, proteins from a variety of biological sources are labeled with biotin. The biotin-labeled proteins are then incubated with antibody chips. Targeted proteins are captured by the array antibodies spotted on the antibody chips. The presence of targeted proteins is detected using Cy3- or Cy5-conjugated streptavidin and signals are imaged by laser scanner. The system also can be easily adapted to a two-color binding assay, allowing measurement of the levels of proteins in a test sample with respect to a reference sample at the same chip. To demonstrate its potential applications, we applied this technology to profile human cytokines, chemokines, growth factors, angiogenic factors and proteases in estrogen receptor (ER)+ and ER- cells. These results suggest that biotin-labeled-based antibody chip technology can provide a practical and powerful means of profiling hundreds or thousands of proteins for research and clinical purposes.

Antibodies↗

PubMed2003

cDNA sequence analysis of seven peptide toxins from the spider Selenocosmia huwena.

Seven cDNAs encoding six toxins HWTX-I, HWTX-II, HWTX-IIIa, HWTX-IV, HWTX-V, HWTX-VII and one lectin SHL-I, from the spider Selenocosmia huwena, were cloned and sequenced. On the basis of their amino acid sequences, we designed and synthesized 3' RACE and 5' RACE primer. By overlapping the two partial cDNA sequences obtained by 3' and 5' RACE, their full-length cDNA sequences were obtained. All of the cDNAs of these seven peptides encode a precursor including a potential signal peptide of 21-24 residues, a mature toxin of about 30 residues and an intervening pro region. The prepro regions of HWTX-I, HWTX-IIIa, HWTX-IV, HWTX-V and SHL-I were demonstrated, by the comparison of the cDNA sequences, to have high similarity, which is concert with the similar inhibitor cystine knot motif of HWTX-I, HWTX-IV and SHL-I although their functions are different. It was also demonstrated that, HWTX-II and HWTX-VII share the highly similar prepro region which is different from that of HWTX-I, HWTX-IV and SHL-I. The three dimensional structure of HWTX-II has been determined to exhibit a different motif. This indicates that the seven peptides from S. huwena could be classified into two different superfamilies according to the prepro region of cDNA sequences.

Amino Acid Sequence↗

PubMed2003

IFN-gamma up-regulation of IL-12 beta 2 receptor is associated with experimental autoimmune uveitis susceptible B10.A mice, but not in EAU resistant BALB/c mice.

IFN-gamma production is a hallmark of Th1 response, and IFN-gamma has multiple roles in Th1 development, depending on the experimental conditions. In this study, the correlation between IFN-gamma and interleukin 12 receptor beta2 (IL-12R beta 2) expression was investigated in experimental autoimmune uveitis (EAU) susceptible B10.A and resistant BALB/c mice. B10.A mice expressed high IL-12R beta 2 on T cells either in the disease target eyes or draining lymph node cells (LNC), and its expression correlated with the Th1-type response. In contrast, BALB/c mice only expressed minimal IL-12R beta 2 in draining LNC and had lower Th1-response. B10.A mice produced more IFN-gamma and generated a higher number of Th1 cells than that of BALB/c in the draining LNC. Furthermore, IL-12R beta 2 expression and STAT4 signaling were inhibited by anti-IFN-gamma mAb in the cultured draining LNC from B10.A mice, but enhanced by adding exogenous IFN-gamma in the cultured cells from BALB/c mice. The IL-12R beta 2 expression on Th1 cells from draining LNC was increased in the presence of IL-12 and IFN-gamma. In conclusion, IFN-gamma production correlated with IL-12R beta 2 expression on Th1-cells and IFN-gamma had a potential to regulate IL-12R beta 2 expression in vivo. This regulatory mechanism might be involved in EAU induction.

Animals↗

PubMed2003

Identification of an epitope of SARS-coronavirus nucleocapsid protein.

The nucleocapsid (N) protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) is a major virion structural protein. In this study, two epitopes (N1 and N2) of the N protein of SARS-CoV were predicted by bioinformatics analysis. After immunization with two peptides, the peptides-specific antibodies were isolated from the immunized rabbits. The further experiments demonstrated that N1 peptide-induced polyclonal antibodies had a high affinity to bind to E. coli expressed N protein of SARS-CoV. Furthermore, it was confirmed that N1 peptide-specific IgG antibodies were detectable in the sera of severe acute respiratory syndrome (SARS) patients. The results indicated that an epitope of the N protein has been identified and N protein specific Abs were produced by peptide immunization, which will be usefull for the study of SARS-CoV.

Amino Acid Sequence↗

PubMed2003

Detection of multiple cytokines by protein arrays from cell lysate and tissue lysate.

Previously we demonstrated that multiple cytokines could be simultaneously detected using an antibody-based protein array system with high sensitivity and specificity from conditioned medium and serum. Here, we created a higher density array system to simultaneously detect 35 cytokines from cell lysates and tissue lysates. This assay combines the advantages of the specificity of enzyme-linked immunosorbent assays (ELISA), sensitivity of enhanced chemiluminescence (ECL), and high-throughput of microspot. In this system, capture antibodies dissolved in methanol were spotted onto polyvinylidene difluoride (PVDF) membranes. The membranes were then incubated with tissue lysates or cell lysates. After removing unbound proteins by extensive washing, the membranes were exposed to horseradish peroxidase (HRP)-conjugated antibody(ies). The signals were visualized with an ECL system. High specificity, sensitivity, and accuracy of this approach were demonstrated. This approach can be used in any general laboratory setting without any sophisticated equipment. It should be feasible to extend this concept to develop a high-throughput protein array system. Combining nitrocellulose membrane-based and PVDF membrane-based approaches, the human cytokine array system can be applied to detect multiple cytokine expression from cell lysate, tissue lysate, serum, plasma, and conditioned medium. Future applications of this new approach include direct protein expression profiling, immunological disease diagnostics, and discovery of new biomarkers.

Biomarkers↗

PubMed2003

Tumor cyclooxygenase 2-dependent suppression of dendritic cell function.

Dendritic cells (DCs) serve as professional antigen-presenting cells and are pivotal in the host immune response to tumor antigens. To define the pathways limiting DC function in the tumor microenvironment, we assessed the impact of tumor cyclooxygenase (COX)-2 expression on DC activities. Bone marrow-derived DCs were cultured in either tumor supernatant (TSN) or TSN from COX-2-inhibited tumors. After culture, DCs were pulsed with tumor-specific peptides, and their ability to generate antitumor immune responses was assessed following injection into established murine lung cancer. In vitro, DC phenotype, alloreactivity, antigen processing and presentation, and interleukin (IL)-10 and IL-12 secretion were evaluated. DCs cultured in TSN failed to generate antitumor immune responses and caused immunosuppressive effects that correlated with enhanced tumor growth. However, genetic or pharmacological inhibition of tumor COX-2 expression restored DC function and effective antitumor immune responses. Functional analyses indicated that TSN causes a decrement in DC capacity to (a) process and present antigens, (b) induce alloreactivity, and (c) secrete IL-12. Whereas TSN DCs showed a significant reduction in cell surface expression of CD11c, DEC-205, MHC class I antigen, MHC class II antigen, CD80, and CD86 as well as a reduction in the transporter-associated proteins, transporter associated with antigen processing 1 and 2, the changes in phenotype and function were not evident when DCs were cultured in supernatant from COX-2-inhibited tumors. We conclude that inhibition of tumor COX-2 expression or activity can prevent tumor-induced suppression of DC activities.

Animals↗

PubMed2003

[Clinical value comparison between chemiluminescent immunoassay and immunoradiometric assay in detecting TSH in serum].

OBJECTIVE: To compare the clinical value between chemiluminescent immunoassay (CLIA) and immunoradiometric assay (IRMA) in detecting TSH in patients with hyperthyroidism and hypothyroidism. METHODS: The TSH levels in serums were detected by CLIA and IRMA in 112 normal persons, 120 hyperthyroidism patients and 58 hypothyroidism patients. RESULTS: CLIA was significantly correlated with IRMA (r = 0.98, P < 0.01). CLIA had higher coincidence rate than IRMA in the diagnosis of hyperthyroidism and hypothyroidism, and CLIA was more accurate and repetitive than IRMA. CONCLUSION: CLIA is more valuable than IRMA in diagnosing both hyperthyroidism and hypothyroidism.

Adult↗

PubMed2002

Profiling of human cytokines in healthy individuals with vitamin E supplementation by antibody array.

Previously, we demonstrated that vitamin E supplementation decreases autoantibodies to oxidized lipid-protein complexes (J. Med. Food 1 (2000) 247). Utilizing an in vitro modeling system, we also demonstrated that vitamin E blocks the tumor promotion process in liver epithelial cells (Carcinogenesis 20 (1999) 485 and Mol. Carcinog. 30 (2001) 209). To investigate the molecular mechanisms of vitamin E function, we developed a human cytokine array system that is capable of detecting the expression of 35 cytokines simultaneously. Using this new technology, we analyzed the potential vitamin E-regulated cytokines in vitamin E supplementation individuals. The cytokine arrays showed that expression of several cytokines, particularly monocyte chemoattractant protein-1 (MCP-1), was profoundly reduced in vitamin E supplementation individuals. Moreover, addition of vitamin E to several cultured cells significantly down-regulated the expression of MCP-1. Our results suggested that MCP-1 may be one of the most important targets of antioxidant vitamin E. To the best of our knowledge, this is the first report describing the down-regulation of MCP-1 in vitamin E supplementation in vivo.

Adolescent↗

PubMed2002

Autocrine/paracrine prostaglandin E2 production by non-small cell lung cancer cells regulates matrix metalloproteinase-2 and CD44 in cyclooxygenase-2-dependent invasion.

Tumor cyclooxygenase-2 (COX-2) expression is known to be associated with enhanced tumor invasiveness. In the present study, we evaluated the importance of the COX-2 product prostaglandin E2 (PGE2) and its signaling through the EP4 receptor in mediating non-small cell lung cancer (NSCLC) invasiveness. Genetic inhibition of tumor COX-2 led to diminished matrix metalloproteinase (MMP)-2, CD44, and EP4 receptor expression and invasion. Treatment of NSCLC cells with exogenous 16,16-dimethylprostaglandin E2 significantly increased EP4 receptor, CD44, and MMP-2 expression and matrigel invasion. In contrast, anti-PGE2 decreased EP4 receptor, CD44, and MMP-2 expression in NSCLC cells. EP4 receptor signaling was found to be central to this process, because antisense oligonucleotide-mediated inhibition of tumor cell EP4 receptors significantly decreased CD44 expression. In addition, agents that increased intracellular cAMP, as is typical of EP4 receptor signaling, markedly increased CD44 expression. Moreover, MMP-2-AS treatment decreased PGE2-mediated CD44 expression, and CD44-AS treatment decreased MMP-2 expression. Thus, PGE2-mediated effects through EP4 required the parallel induction of both CD44 and MMP-2 expression because genetic inhibition of either MMP-2 or CD44 expression effectively blocked PGE2-mediated invasion in NSCLC. These findings indicate that PGE2 regulates COX-2-dependent, CD44- and MMP-2-mediated invasion in NSCLC in an autocrine/paracrine manner via EP receptor signaling. Thus, blocking PGE2 production or activity by genetic or pharmacological interventions may prove to be beneficial in chemoprevention or treatment of NSCLC.

Antigens, CD↗

PubMed2002

Identification of the amino acid residues in trichosanthin crucial for IgE response.

Trichosanthin (TCS) is the major effective component from Chinese herb Trichosanthes kirilowii. TCS has been approved to be effective in clinical treatment of HIV infection and leukemia, but its allergenicity has limited its clinical usage. To identify amino acid residues in TCS with an important role in IgE induction, TCS-specific IgE mAb (TE1) was used to serve as a probe and TE1 epitope was determined by a random phage-peptide library. Based on phage peptide sequences, TE1 epitope was predicted at amino acid residues 169-174 (QQIGKR) of TCS protein. Based on modeling data, two amino acids (Lys173 and Arg174) on TCS were considered to have a crucial role in binding to TE1. After lysine 173 and arginine 174 were mutated to glycine, the mutant TCS protein specifically lost the binding activity to TE1 mAb and exhibited reduced IgE induction in the immunized mice. The data showed that the IgE epitope of TCS was determined and shown to play a critical role in induction of IgE, and the modification of IgE-epitope may be a useful strategy to reduce the allergenicity of an allergen.

Amino Acid Sequence↗

PubMed2002

Connexin 43 suppresses human glioblastoma cell growth by down-regulation of monocyte chemotactic protein 1, as discovered using protein array technology.

Previously, we demonstrated that connexin 43 (cx43) suppressed the growth of human glioblastoma cells. To investigate the molecular mechanisms involved in tumor suppression by cx43, we developed a human cytokine array system, which simultaneously detects the expression of 43 cytokines. By using this new technology, we analyzed the cx43-regulated genes in cx43-transfected cells. The cytokine arrays showed that expression of monocyte chemotactic protein-1 (MCP-1) was profoundly reduced in cx43-transfected cells. RT-PCR, immuno-Western blot, and cDNA microarrays further confirmed this observation. Addition of conditioned medium from control-transfected cells and recombinant MCP-1 to cx43-transfected cells significantly enhanced cx43-transfected cell proliferation and colony formation in soft agar. In contrast, addition of neutralization antibody against MCP-1 significantly inhibited cell proliferation in control-transfected cells. Our results suggested that MCP-1 is involved in the suppression of human glioblastoma cell growth by cx43.

Cell Division↗

PubMed2002

Analysis of gene expression in Egr-1 transfected human fibrosarcoma cells.

BACKGROUND AND OBJECTIVES: It has been shown previously that transcription factor Egr-1 functions as a tumor suppressor gene. This study was conducted to investigate the possible mechanisms responsible for this function. METHODS: A cDNA microarray technique was applied to study differential gene expression between Egr-1-transfected cells and control-transfected cells. RESULTS: A number of genes differentially expressed were identified. Among 5,184 genes examined by cDNA microarray technique, 53 were up-regulated in Egr-1 transfected cells, and 276 were down-regulated in Egr-1 transfected cells by at least two times or more; 13 genes were independently confirmed by reverse transcription polymerase chain reaction (RT-PCR). Of these 13 genes, 11 were in agreement with cDNA microarrays in terms of gene expression levels. CONCLUSIONS: Egr-1 regulated almost every category of genes according to gene ontology system, and repressed more genes than it induced. The identification and further characterization of genes regulated by Egr-1 should provide valuable information to understand Egr-1 tumor suppressor action and the role of Egr-1 as a transcription factor in general.

DNA-Binding Proteins↗

PubMed2002

Cell type-specific expression and coregulation of murine resistin and resistin-like molecule-alpha in adipose tissue.

Adipocytes are the exclusive or predominant source of several secreted proteins that exert profound effects on systemic carbohydrate and lipid metabolism. Resistin, a 10-kDa adipose tissue specific secretory protein, has recently been implicated in exerting a negative effect on systemic insulin sensitivity. It is, however, not known how resistin mediates this insulin-desensitizing effect or what regulatory mechanisms control resistin expression. Resistin-like molecule-alpha (RELMalpha), a homolog of resistin originally identified by its upregulation in asthmatic lung, is another secreted protein expressed in adipose tissue. The regulation of RELMalpha in adipose tissue and its relationship to resistin expression has not been addressed so far. Here, we demonstrate that the expression of resistin and RELMalpha are similarly regulated in adipose tissue despite the fact that RELMalpha is exclusively expressed in the stromal vascular fraction of adipose tissue and not in adipocytes. Interestingly, this coregulation is limited to adipose tissue as the expression of RELMalpha in lung is independent of metabolic regulation. Additionally, we show that resistin and RELMalpha levels are not subject to regulation by proinflammatory stimuli. Finally, acute hyperglycemia leads to up-regulation of resistin and RELMalpha transcription in various adipose depots.

3T3 Cells↗

PubMed2002

Effects of recombinant human growth hormone on rat septic shock with intraabdominal infection by E. coli.

AIM: To investigate the therapeutic effects of recombinant human growth hormone (rhGH) on rat septic shock with intraabdominal infection by E. coli and its possible mechanism. METHODS: 76 SD rats were divided into 3 groups randomly: control group (group C, n=16) without any special treatment, septic shock group (group S, n=30) received bolus injection of E.coli (1X10(10) cfu x L(-1), 15 ml x kg(-1), ip), treated group (group T, n=30) received bolus injection of E.coli, and then followed by rhGH injection (2.25 U x k g(-1) x d(-1), im). Group S and group T were further divided into 1d and 3d subgroups, respectively (n=15 each). Mean arterial pressure (MAP), levels of plasma TNFalpha and endotoxin and leukocyte count were determined on 1st day and 3rd day after E.coli injection. Another 39 SD rats were divided into groups C, S and T (n=13 each) just for observing survival rate within 1 week. RESULTS: (1) On 1st and 3rd day, MAP in group S decreased markedly, and MAP on 1st day lowered more than that of 3rd day (P<0.01), while MAP in group T just decreased slightly. The survival rate within 1 week was much higher in group T (84.6 %) than in group S (46.2 %) (P<0.01). (2)On 1st day, plasma TNFalpha and endotoxin elevated significantly in group S and group T (P<0.05), and endotoxin in group S had more increase (P<0.01). On 3rd day, TNFagr in group S returned to the level of group C (P>0.05),while TNFagr in group T went down below the level of group C(P<0.01). On 3rd day, endotoxin in group S declined, but was still higher than that of group C (P<0.01), endotoxin in group T returned to the level of group C (P>0.05). (3) On 1st day, neutrophil ratio in total leukocyte count in both group S and group T increased significantly (P<0.05 vs group C). CONCLUSION: rhGH showed beneficial effects on rat septic shock. The possible mechanisms may involve the attenuation of bacteria/endotoxin translocation and decreased systemic endotoxin level; inhibition of the production and release of TNFalpha; improved circulatory function; improved systemic host defenses and maintenance of intestinal mucosa barrier.

Abdomen↗