The TGF-β signaling modulators TRAP1/TGFBRAP1 and VPS39/Vam6/TLP are essential for early embryonic development

The pleiotropic cytokine transforming growth factor-β (TGF-β) signals through different pathways among which the Smad- and the MAP-Kinase pathways are already well characterized. Both pathways utilize adaptor/chaperone molecules that facilitate or modulate the intracellular signaling events. Two of the proteins shown in vitro to play a role in Smad-dependent signaling are the TGF-β Receptor Associated Protein-1 (TRAP1, also TGFBRAP1) and its homologue VPS39, also known as Vam6 and TRAP1-Like-Protein (TLP). We generated mice deficient for TRAP1 and VPS39/TLP, respectively. Absence of TRAP1 protein results in death at either of two defined timepoints during embryogenesis, before the blastula stage or during gastrulation, whereas most of the VPS39 deficient mice die before E6.5. Heterozygous mice show no overt phenotype. In summary, our data indicate that TRAP1 and VPS39 are nonredundant and essentially required for early embryonic development.     

蛇床子素对体外培养破骨细胞骨吸收及细胞凋亡的影响

研究蛇床子素对破骨细胞骨吸收的影响及其分子机制。采用体外分离、培养兔破骨细胞, 与盖玻片及骨磨片共同培养, 使用1×10⁻⁵ mol·L⁻¹蛇床子素刺激破骨细胞, 观察活体细胞并依据HE、TRAP、骨陷窝甲苯胺蓝染色鉴定破骨细胞; 进行骨吸收陷窝和面积定量分析, 吖啶橙染色统计凋亡细胞; real time PCR及Western blotting法检测相关基因和蛋白。与空白对照组比较, 1×10⁻⁵ mol·L⁻¹蛇床子素能够明显提高破骨细胞凋亡率并通过抑制RANKL和TRAP等相关基因及JNK1/2磷酸化水平抑制其骨吸收。结果提示, 蛇床子素可以通过RANK+RANKL/ TRAF6/Mkk/JNK途径刺激破骨细胞凋亡并抑制骨吸收。     

胃息肉组织中端粒酶活性的检测及其临床意义

目的：探讨端粒酶在胃息肉中的检测及临床意义。方法：标本均系电子内镜下取得的胃息肉组织5块,3块送活检,另2块进行端粒酶活性检测。结果：增生性息肉、腺瘤、炎性息肉、幼年性息肉和息肉样胃癌组织的端粒酶阳性率分别为6．6％、18％、13．5％、0％和88％。结论：端粒酶活性检测可作为胃息肉恶变的早期预测指标。     

Cystic fibrosis heterozygotes do not have increased platelet activation

INTRODUCTION: We have previously demonstrated platelet hyperreactivity in cystic fibrosis (CF) patients. Carriers of one CF mutation (heterozygotes) have been shown to have abnormalities related to the presence of only one-half the normal amount of CF transmembrane conductance regulator protein. Platelet hyperreactivity in CF heterozygotes would be an important cardiovascular risk factor, since approximately 1 in 25 Caucasians is a CF carrier. MATERIALS AND METHODS: We used highly sensitive assays of platelet activation to assess the difference between 16 CF heterozygotes and 16 age- and sex-matched healthy controls without CF mutations. RESULTS: We found no difference in platelet activation between CF heterozygotes and controls. CONCLUSIONS: The 50% reduction in the CF transmembrane conductance regulator protein in heterozygotes is insufficient to cause platelet activation.     

Ex vivo microvesicle formation after prolonged ischemia in renal transplantation

INTRODUCTION: Patients with chronic renal failure suffer from dysfunction in coagulation. Kidney transplantation induces inflammatory reactions and thus activation of platelets. Activated platelets, in turn, form microvesicles by shedding. These microvesicles have been shown to have coagulant activities. Activated platelets in prolonged cold ischemia were associated with delayed graft function and inferior survival. We investigated ex vivo formation of microvesicles in kidney transplantation and the influence of cold graft storage on microvesicles. METHODS: 20 patients (47.4+/-10.6 years (mean+/-SD)) undergoing transplantation were included in the study after written informed consent. Dependent on cold preservation time of transplanted kidneys, recipients were allocated into two groups with 10.4+/-6.1 h (group 1) and 23.7+/-3.8 h (group 2) preservation time, respectively. Blood samples were drawn before anesthesia, 12 h, 2, 7 and 14 days after transplantation. To evaluate microvesicle release, samples were activated with thrombin-receptor-activating-peptide-6 (TRAP) or adenosine-di-phosphate. Microvesicles were counted as percentage of platelets smaller than a predetermined size in flow cytometry. RESULTS: Platelet derived ex vivo microvesicle formation was significantly higher up to 48 h after transplantation when stimulated with TRAP in group 1. Platelet count was significantly higher compared to baseline values in the short-term ischemia group but not with long-term ischemia. Creatinine was significantly lower at study end compared to baseline with no differences between both groups. CONCLUSIONS: Lower platelet microvesicle formation after ex vivo stimulation with TRAP was associated with longer graft ischemia time. This may be a sign of former activation of platelets which could influence graft function and survival.     

Neutrophil CD40 enhances platelet-mediated inflammation

INTRODUCTION: CD40 is a transmembrane protein expressed on monocytes, macrophages, endothelial cells, and platelets. Platelets are the richest source of soluble CD40 ligand (sCD40L) and interact with monocytes and endothelial cells via CD40. While CD40 was recently reported to be present on neutrophils, the detailed mechanism of its interaction with platelets via CD40-CD40L has not been examined. MATERIALS AND METHODS: The existence of neutrophil CD40 was verified by real-time PCR and western blot. Platelet sCD40L release was measured by ELISA. Neutrophil superoxide generation was measured by chemiluminescence and confocal microscopy. The neutrophil-platelet conjugates were measured by flow cytometry. RESULTS AND CONCLUSION: The presence of neutrophils enhances stimulation-induced platelet release of sCD40L. The addition of platelets leads to an enhancement of neutrophil superoxide and reactive oxygen species (ROS) generation. The specificity of the CD40-CD40L pathway in the neutrophil-platelet interaction was confirmed by using recombinant soluble CD40L (rsCD40L) and an anti-CD40L antibody. The involvement of the PI3 kinase/Akt pathway in neutrophil superoxide production was revealed by using LY294002 in isolated neutrophils/platelets experiments, as well as during whole blood aggregation-mediated neutrophil-platelet conjugation. N-acetylcysteine, a scavenger of ROS, eliminates both neutrophil superoxide generation and sCD40L release from activated platelets. These data suggest that activated neutrophils release ROS in a PI3 kinase-dependent manner, contributing to platelet activation and further sCD40L release in a redox-controlled positive feed-back loop. In conclusion, our results define a new pathway by which platelets and neutrophils interact and modulate each other's function, and may be relevant in understanding acute thrombo-inflammatory processes.     

Biochemical markers in oncology. Part I: molecular basis. Part II: clinical uses

The investigation of the molecular mechanisms involved in carcinogenesis and tumor progression has led to the development of numerous biochemical markers. Biochemical markers may serve for early prediction of tumor recurrence, progression and development of metastases including bone metastases and for prediction of response to therapy. Tumor antigens have been used for more than a decade and although they have shown promising clinical results, their sensitivity and specificity remain limited. A lot of knowledge on the key molecules which control cell cycle, apoptosis and angiogenesis has been acquired during recent years, but their clinical value remains uncertain. Molecular markers which are linked to malignant transformation may provide a non-surgical therapeutic approach by targeting these molecules through gene therapy or antisense molecules. Because of the complexity of the physiopathogical processes involved in tumorogenesis and metastases, we first provide a review on the molecular basis of the various tumor markers and then discuss their potential clinical utility for the major cancers. The review of the current literature indicates that at the exception of a few examples, such as the use of Her-2 to predict response of the targeted Herceptin therapy, no single marker is sensitive and specific enough to perform an accurate diagnosis, predict disease progression or response to treatment. A combination of different biochemical and imaging markers appears to be the most promising strategy to monitor patients with cancer.     

Telomerase activity in gastric cancer

OBJECTIVE : To examine telomerase activity and its clinical significance in human gastric carcinoma and to evaluate the feasibility of non‐radioisotopic TRAP (telomeric repeat amplification protocol) assays to detect telomerase activity. METHODS : Telomerase activity in tissue samples from 58 gastric carcinomas (and their matched normal tissues), 12 gastric adenomas and nine gastric ulcers was examined by using a modified non‐ radioisotopic PCR (polymerase chain reaction)‐based TRAP assay. RESULTS : Forty‐nine of 58 gastric cancer specimens were positive for telomerase activity, with a positive rate of 84.5%. In contrast, none of the normal tissues exhibited telomerase activity (P < 0.001). One of each of the 12 gastric adenomas and nine gastric ulcers was also positive. The prevalence of telomerase activity in gastric carcinoma tissues was not correlated with age, tumor diameter, histological grade, tumor invasion depth, lymph node metastasis or tumor node metastasis (TNM) stage. CONCLUSIONS : Telomerase activity could be a good diagnostic marker for the detection of gastric carcinoma. The non‐radioisotopic TRAP assay is a feasible method for detecting telomerase activity.