The structure and function of the glycoprotein (GP) Ib-IX-V complex has been extensively investigated over the decades due to its vital role in platelet activation. For the lack of nucleus in platelets, researchers usually need to study the GPIb-IX-V complex by transfecting wild type or mutant GPIb-IX-V plasmids into other mammalian cell lines, such as CHO or HEK 293T. Therefore, whether the characteristics of the GPIb-IX-V complex in these cell lines can truly represent that in platelets is pivotal to determine whether these cell lines are appropriate for GPIb-IX-V complex studies. In order to determine the most appropriate cell line to study the GPIb-IX-V complex, the surface expression level of the complex in different cell lines was detected and whether difference among cell lines will affect expression of the complex was explored in the present study. The different combinations of the GPIb-IX-V subunits were transfected into cell lines from different species or different tissues, such as CHO, HEK293T and HeLa, and the surface expression levels of the complex were detected by flow cytometry. The results indicated that in both transiently and stably transfected CHO cells, surface expression of GPV depended on the presence of the GPIb-IX complex, which is consistent with that in human platelets. In contrast, GPV could be efficiently expressed on surface in HEK 293T cells even in the absence of GPIb-IX, although the inter-subunit dependence within the GPIb-IX complex is still similar to that in CHO cells or human platelets. Further studies in HeLa, MES13 and HUVEC cell lines revealed that GPV could be efficiently expressed on the surface by itself in HeLa and MES13 cells, but not in HUVEC, suggesting different behaviors of the GPIb-IX-V complex in difference cell lines. It is concluded that this study provides some guidance and advice to future GPIb-IX-V complex studies, especially to the choice of suitable cell line. HEK 293T cell line, for example, is likely to provide misleading results since it could not represent the fact in human platelets, thus is not the optimal choice for the GPIb-IX-V complex, particularly the GPV subunit.
Animals ; CHO Cells ; Cricetinae ; Cricetulus ; HEK293 Cells ; metabolism ; Humans ; Platelet Glycoprotein GPIb-IX Complex ; genetics ; metabolism ; Transfection

OBJECTIVETo study the platelet morphology and function of an inherited macrothrombocytopenia disorder with abnormal large granules.

METHODSPlatelet size and structure were investigated by both light microscopy and electron microscopy. The platelet membrane expression of GP I b, GP II b, GPIII a, P-selectin and CD63 were analyzed by using respective monoclonal antibodies. Platelet 5-hydroxy-tryptamine was measured with spectrophotofluorometer.

RESULTSBoth the patient and her father had large granules in their platelets, with exocytosis being easily observed. The expressions of GP I b, GP II b and GP II a on the platelets were in normal range, while P-selectin and CD63 were somewhat increased. The abnormal large granules were not the alpha granules, lysosomes or dense bodies.

CONCLUSIONBoth morphological and functional abnormalities of the platelets from the patient are clearly distinguishable from other hereditary giant platelet disorders. It would probably represent a novel platelet disorder.

Adult ; Blood Platelets ; metabolism ; ultrastructure ; Female ; Humans ; Integrin beta3 ; biosynthesis ; Microscopy, Immunoelectron ; Platelet Glycoprotein GPIb-IX Complex ; biosynthesis ; Platelet Membrane Glycoprotein IIb ; biosynthesis ; Thrombocytopenia ; genetics ; pathology

OBJECTIVETo explore the role of the amino acids between 551 and 565 in the cytoplasmic domain of glycoprotein (GP) I b alpha in the VWF binding to GP I b alpha.

METHODSThe VWF binding to GP I b alpha induced by ristocetin was analyzed by flow cytometry, in three GP I b-IX-expressing Chinese hamster ovary (CHO) cell lines 1b9, delta 565 and delta 551, adhesion of above cells on VWF by flow chamber analysis at shear rate of 200 s(-1). The spread of GP I b-IX-expressing cells were stimulated with botrocetin on VWF-coated coverslips by confocal microscope.

RESULTSThe VWF binding to GP I b alpha was higher in delta 565 cells stimulated by ristocetin than in delta 551 or 1b9 cells. The number of delta 565 cells adhered on the VWF-coated-chamber was more than that of controls at shear rate of 200 s(-1). Moreover, the surface spreading areas of delta 565 cells were greater than that of the controls on VWF-coated coverslips.

CONCLUSIONSThe amino acids between 551 and 565 in the cytoplasmic domain of GP I b alpha regulates the VWF binding to GP I b alpha.

Amino Acid Sequence ; Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Female ; Platelet Adhesiveness ; Platelet Glycoprotein GPIb-IX Complex ; genetics ; metabolism ; von Willebrand Factor ; metabolism

We performed gene expression profiling in bladder cancer patients to identify cancer-specific survival-related genes in muscle invasive bladder cancer (MIBC) patients. Sixty-two patients with MIBC were selected as the original cohort and another 118 MIBC patients were chosen as a validation cohort. The expression of USP18, DGCR2, and ZNF699 genes were measured and we analyzed the association between gene signatures and survival. USP18 and DGCR2, were significantly correlated to cancer-specific death (P=0.020, P=0.007, respectively). Cancer-specific survival in the low USP18 or DGCR2 expression group was significantly longer than the high expression group (P=0.018, P=0.006, respectively). In multivariate Cox regression analysis, a combination of USP18 and DGCR2 mRNA expression levels were significant risk factors for cancer-specific death (HR, 2.106; CI, 1.043-4.254, P=0.038). Overall survival and cancer-specific survival rates in the low-combination group were significantly longer than those in the high-expression group (P=0.001, both). In conclusion, decreased expressions of USP18 and DGCR2 were significantly associated with longer cancer-specific survival, and also the combination of two genes was correlated to a longer survival for MIBC patients. Thus, the combination of USP18 and DGCR2 expression was shown to be a reliable prognostic marker for cancer-specific survival in MIBC.
Adult ; Aged ; Aged, 80 and over ; Biological Markers/metabolism ; Carrier Proteins/genetics/metabolism ; Endopeptidases/genetics/*metabolism ; Female ; Gene Expression Profiling ; Humans ; Kaplan-Meier Estimate ; Male ; Middle Aged ; Muscle Neoplasms/*secondary ; Neoplasm Invasiveness ; Neoplasm Staging ; Platelet Glycoprotein GPIb-IX Complex/genetics/*metabolism ; Predictive Value of Tests ; ROC Curve ; Regression Analysis ; Risk Factors ; Urinary Bladder Neoplasms/*diagnosis/metabolism/*mortality/pathology

OBJECTIVETo investigate the association of serotonin transporter gene linked polymorphic region (5-HTTLPR) insertion/deletion polymorphism with early onset myocardial infarction(MI) and platelet membrane glycoprotein I b(GP I b) in Northern Han population of China.

METHODSA total of 150 patients with early onset MI and 150 age- and sex-matched controls with negative coronary arteriography were genotyped for the 5-HTTLPR polymorphism by using a polymerase chain reaction-based technique. The percentage of positive platelet membrane GP I b and the average fluorescence intensity were quantified by flow cytometry.

RESULTSThe genotype frequencies of LL, LS and SS in the 5-HTTLPR were 32%, 47% and 21% in the MI patients, 17%, 43% and 39% in the controls respectively(P<0.01). The L allele frequency in the MI patients was significantly higher than that of the control group (56% vs 39%, P<0.01). The percentage of positive platelet membrane GP I b and the fluorescence intensity in subjects with LL homozygote were markedly lower than that of LS and SS genotypes in the MI and control groups (all P<0.01). Multivariate logistic regression analysis showed that the 5-HTTLPR LL genotype was independently related to the occurrence of early onset MI(OR was 1.961, P was 0.037).

CONCLUSIONThe LL genotype of the 5-HTTLPR might be associated with the susceptibility to developing early MI in Northern Han population of China. The platelet activation is increased in individuals of LL genotype.

Adult ; Age of Onset ; Alleles ; Asian Continental Ancestry Group ; genetics ; Case-Control Studies ; Ethnic Groups ; genetics ; Female ; Gene Frequency ; Homozygote ; Humans ; INDEL Mutation ; Logistic Models ; Male ; Middle Aged ; Myocardial Infarction ; genetics ; metabolism ; pathology ; Platelet Glycoprotein GPIb-IX Complex ; metabolism ; Polymorphism, Genetic ; Serotonin Plasma Membrane Transport Proteins ; genetics