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Biomedical subjects

Jie Huang

Publications and source records attributed to Jie Huang.

At least 37 records · Page 2Linked to original sources

The MAX-interacting transcription factor network.

The small bHLHZip protein MAX functions at the center of a transcription factor network that governs many aspects of cell behavior, including cell proliferation and tumorigenesis. MAX serves as a cofactor for DNA binding by the various members of this network, which include the MYC family of oncoproteins and a group of putative MYC antagonists that include MNT, MXD1-4 (formerly MAD1, MXI1, MAD3 and MAD4) and MGA. The many heterodimerization partners of MAX raises questions concerning the dynamics of MAX interactions and the functional consequences of the switching of Max partners. Here we review the activities of MAX, its interaction partners, and recent results showing that tissues lacking the MAX-interacting protein MNT are predisposed to tumor formation.

Animals↗

Protein kinase Cepsilon activates protein kinase B/Akt via DNA-PK to protect against tumor necrosis factor-alpha-induced cell death.

We have previously shown that protein kinase Cepsilon (PKCepsilon) protects breast cancer cells from tumor necrosis factor-alpha (TNF)-induced cell death. In the present study, we have investigated if the antiapoptotic function of PKCepsilon is mediated via Akt and the mechanism by which PKCepsilon regulates Akt activity. TNF caused a transient increase in Akt phosphorylation at Ser473 in MCF-7 cells. Overexpression of PKCepsilon in MCF-7 cells increased TNF-induced Akt phosphorylation at Ser473 resulting in its activation. Knockdown of PKCepsilon by small interfering RNA (siRNA) decreased TNF-induced Akt phosphorylation/activation and increased cell death. Introduction of constitutively active Akt protected breast cancer MCF-7 cells from TNF-mediated cell death and partially restored cell survival in PKCepsilon-depleted cells. Depletion of Akt in MCF-7 cells abolished the antiapoptotic effect of PKCepsilon on TNF-mediated cell death. Akt was constitutively associated with PKCepsilon and DNA-dependent protein kinase (DNA-PK), and this association was increased by TNF treatment. Overexpression of PKCepsilon enhanced the interaction between Akt and DNA-PK. Knockdown of DNA-PK by siRNA inhibited TNF-induced Akt phosphorylation and the antiapoptotic effect of Akt and PKCepsilon. These results suggest that PKCepsilon activates Akt via DNA-PK to mediate its antiapoptotic function. Furthermore, we report for the first time that DNA-PK can regulate receptor-initiated apoptosis via Akt.

Apoptosis↗

[Surgical anatomy of the colic vessels in Chinese and its influence on the operation of esophageal replacement with colon].

OBJECTIVE: To investigate the configuration of colic vessels in Chinese and its influence on the operation of esophageal replacement with colon (ERC). METHODS: The origin, trend, branching, configuration, and distribution of the colic vessels, the intensity of the colic arterial impulse, the integrity of the marginal artery at the splenic flexure and hepatic flexure of colon were observed during the operation of ERC among 582 patients undergoing ERC, 402 males mad 180 females, aged 2 approximately 74, from 22 provinces, municipality, and autonomous regions. RESULTS: The left colic artery (LCA) stemmed from the inferior mesenteric artery (IMA) in 97.3% of the patients, with an absence rate of 0.7%. The middle colic artery (MCA) stemmed from the superior mesenteric artery (SMA) in 77.8% of the patients with an absence rate of 8.2%. Accessory middle colic artery (acMCA), originating from the right colic artery, could be seen in 6.2% of the patients 39.7% of the right colic artery (RCA) stemmed from the SMA by itself, 23.0% of the RMA stemmed together with MCA, and 28.0% of the RCA stemmed together with the ileocolic artery. The absence rate of RCA was 9.8%. The intactness rate of marginal artery was 96.8% at the splenic flexure of colon, and was 88.7% at the hepatic flexure. The Rolan arch was seen in only 7.6% of the patients. CONCLUSION: The configuration of colic vessels in Chinese was basically similar to those of the results of autopsies carried out abroad. The optimal supply artery of colic segment during ERC is LCA, followed by LCA. Attention should be paid to the integrity of marginal arteries and veins in the patients with history of epigastric operation.

Adolescent↗

Unintended consequences of caps on Medicare drug benefits.

BACKGROUND: Little information exists about the consequences of limits on prescription-drug benefits for Medicare beneficiaries. METHODS: We compared the clinical and economic outcomes in 2003 among 157,275 Medicare+Choice beneficiaries whose annual drug benefits were capped at 1,000 dollars and 41,904 beneficiaries whose drug benefits were unlimited because of employer supplements. RESULTS: After adjusting for individual characteristics, we found that subjects whose benefits were capped had pharmacy costs for drugs applicable to the cap that were lower by 31 percent than subjects whose benefits were not capped (95 percent confidence interval, 29 to 33 percent) but had total medical costs that were only 1 percent lower (95 percent confidence interval, -4 to 6 percent). Subjects whose benefits were capped had higher relative rates of visits to the emergency department (relative rate, 1.09 [95 percent confidence interval, 1.04 to 1.14]), nonelective hospitalizations (relative rate, 1.13 [1.05 to 1.21]), and death (relative rate, 1.22 [1.07 to 1.38]; difference, 0.68 per 100 person-years [0.30 to 1.07]). Among subjects who used drugs for hypertension, hyperlipidemia, or diabetes in 2002, those whose benefits were capped were more likely to be nonadherent to long-term drug therapy in 2003; the respective odds ratios were 1.30 (95 percent confidence interval, 1.23 to 1.38), 1.27 (1.19 to 1.34), and 1.33 (1.18 to 1.48) for subjects using drugs for hypertension, hyperlipidemia, and diabetes. In each subgroup, the physiological outcomes were worse for subjects whose drug benefits were capped than for those whose benefits were not capped; the odds ratios were 1.05 (95 percent confidence interval, 1.00 to 1.09), 1.13 (1.03 to 1.25), and 1.23 (1.03 to 1.46), respectively, for subjects with a systolic blood pressure of 140 mm Hg or more, a serum low-density-lipoprotein cholesterol level of 130 mg per deciliter or more, and a glycated hemoglobin level of 8 percent or more. CONCLUSIONS: A cap on drug benefits was associated with lower drug consumption and unfavorable clinical outcomes. In patients with chronic disease, the cap was associated with poorer adherence to drug therapy and poorer control of blood pressure, lipid levels, and glucose levels. The savings in drug costs from the cap were offset by increases in the costs of hospitalization and emergency department care.

Antihypertensive Agents↗

[The clinical value of B-type natriuretic peptide in the diagnosis of left heart failure].

OBJECTIVE: To evaluate the diagnostic value of B-type natriuretic peptide (BNP) in the diagnosis of left heart failure (HF) or left ventricular systolic dysfunction. METHODS: Samples of peripheral venous blood were collected from 243 consecutive patients with left HF and 111 normal controls (control group, CG) to measured BNP level with fluorescence immunoassay method. The patients with left HF were divided into 2 groups: those with the left ventricular ejection fraction (LVEF) </= 40% (n = 111) and those with the LVEF > 40% (n = 132) according to the level of LVEF; or into 2 groups: compensated heart failure group (CHF group, at NYHA grade I - II, n = 110) and decompensated heart failure group (DHF group, at NYHA grade III - IV, n = 133) according to the New York Heart Association (NYHA) functional class. RESULTS: The plasma level of BNP of the left HF group was 292.0 ng/L, significantly higher than that of the CG (17.9 ng/L, P < 0.001). The plasma BNP of the group with the LVEF </= 40% was 471.0 ng/L, significantly than that of the group with the LVEF > 40% (138.5 ng/L, P < 0.001). The plasma BNP of the DHF group was 579.0 ng/L, significantly higher than that of the of the CHF group (84.8 ng/L, P < 0.001). The values of area under the curve (AUC) of receiver operator characteristic curve were all > 0.9 in the diagnosis of presence of HF (AUC = 0.927), HF with the LVEF </= 40% (AUC = 0.989), and DHF (AUC = 0.991), and in the differential diagnosis between CHF and DHF (AUC = 0.941). When 90.0 pg/ml was used as cutoff value to diagnose left HF, heart failure with the LVEF </= 40%, and decompensation, the positive predictive value (PPV) were 98.9%, 98.1%, and 98.5% respectively, and the negative predictive value (NPV) were 64.5%, 94.0%, and 96.5% respectively. When 50.0 pg/ml was used as the cutoff value to diagnose HF with the LVEF > 40% and compensated heart failure, the PPV were 88.0% and 84.7%, the NPV were 72.6% and 72.1% respectively. CONCLUSION: The diagnostic value of BNP is high for the diagnosis of more severely impaired LVEF and decompensated heart failure with 90.0 pg/ml as the cutoff value, and if 50.0 pg/ml is used as the cutoff value, the value is also good for the diagnosis of HF with the LVEF > 40% and compensated heart failure.

Adolescent↗

Reduction in V1 activation associated with decreased visibility of a visual target.

The perception of a brief visual target stimulus can be affected by another visual mask stimulus immediately preceding or following the target. The link of this visual masking illusion, with visual cortical activation, offers insights into the neural mechanisms for visual perception. The present study investigated the association of the visibility of a target with cortical activation in humans using psychophysical testing and functional magnetic resonance imaging (fMRI). A visual masking protocol that was suitable for an fMRI study was developed. The event-related fMRI was used to measure activation in primary visual cortex (V1) during visual masking and unmasking stimulation. We found that the visibility of the target stimulus was reduced in the masking condition, due to the presence of mask stimuli, but not in the unmasking condition. We also found that the activation in V1 was modulated by the temporal separation of the mask stimuli from the target and was associated with the visibility of the target that was recorded during psychophysical testing and fMRI. These findings are consistent with what has been observed in the primate visual cortex of monkeys, i.e., the transient on-response and after-discharge of V1 neurons to the target stimulus were suppressed by forward and backward mask stimuli, respectively.

Data Interpretation, Statistical↗

Human degenerative valve disease is associated with up-regulation of low-density lipoprotein receptor-related protein 5 receptor-mediated bone formation.

OBJECTIVES: The goal of this research was to define the cellular mechanisms involved in myxomatous mitral valve disease and calcific aortic valve disease and to redefine the term degenerative valve disease in terms of an active cellular biology. BACKGROUND: "Degenerative" valvular heart disease is the primary cause of regurgitant and stenotic valvular lesion in the U.S. However, the signaling pathways are not known. We hypothesize that valve degeneration occurs due to an osteoblastic differentiation process mediated by the low-density lipoprotein receptor-related protein 5 (Lrp5) signaling pathway to cause valve thickening. METHODS: We examined human diseased valves: myxomatous mitral valves (n = 23), calcified tricuspid aortic valves (n = 27), calcified bicuspid aortic valves (n = 23), and control tissue from mitral and aortic valves (n = 40). The valves were examined by reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry for signaling markers important in osteoblast differentiation: Sox9 and Cbfa1 (transcription factors for osteoblast differentiation); Lrp5 and Wnt3 (osteoblast differentiation signaling marker), osteopontin and osteocalcin (osteoblast endochrondral bone matrix proteins), and proliferating cell nuclear antigen (a marker of cell proliferation). Cartilage development and bone formation was measured by Alcian blue stain and Alizarin red stain. Computed Scano MicroCT-40 (Bassersdorf, Switzerland) analysis measured calcium burden. RESULTS: Low-density lipoprotein receptor-related protein 5, osteocalcin, and other osteochrondrogenic differentiation markers were increased in the calcified aortic valves by protein and gene expression (p > 0.001). Sox9, Lrp5 receptor, and osteocalcin were increased in myxomatous mitral valves by protein and gene expression (p > 0.001). MicroCT was positive in the calcified aortic valves and negative in the myxomatous mitral valves. CONCLUSIONS: The mechanism of valvular heart disease involves an endochondral bone process that is expressed as cartilage in the mitral valves and bone in the aortic valves. Up-regulation of the Lrp5 pathway may play a role in the mechanism for valvular heart disease.

Aged↗

[Classification and surgical treatment of intrathoracic esophageal injury caused by foreign body].

OBJECTIVE: To investigate the classification criterion and surgical treatment strategy of intrathoracic esophageal injury caused by foreign body. METHODS: Eighty-four patients with intrathoracic esophageal injury caused by foreign body in our department from January 1980 to April 2004 were divided into 4 grade: grade I was non-penetrated injury of esophagus (18 cases); grade II was esophageal perforation with mild mediastinitis (39 cases); grade III was esophageal perforation with severe intrathoracic infection (17 cases); grade IV was aortoesophageal fistula (10 cases). Based on the degree of esophageal injury and the extension of inflammation, operative procedures were selected including esophagotomy, esophageal reparation, esophagectomy, mediastinal drainage, reparation of fistula and replacement of aorta. RESULTS: Patients in grade I and II were all cured . One death occurred in grade III (1/17), the same in Grade IV was 9 (9/10). CONCLUSIONS: Classification of esophageal injury caused by foreign body is helpful to the decision of surgical treatment strategy. The prevention of aortoesophageal fistula is the key point of reducing of mortality.

Adolescent↗

Amplitude modulation and apodization of quasiphase-matched interactions.

We propose several techniques to modulate the local amplitude of quasi-phase-matched (QPM) interactions in periodically poled lithium niobate waveguides and demonstrate apodization by using each of these techniques. When the hard edges are removed in the spatial profile of the nonlinear coupling, the sidelobes of the frequency tuning curves are suppressed by 13 dB or more, compared with a uniform grating, consistent with theoretical predictions. The sidelobe-suppressed gratings are useful for frequency conversion devices in optical communication systems to minimize interchannel cross talk, while the amplitude modulation techniques in general have potential uses in applications that require altering the tuning curve shapes.

Journal Article↗

The response of osteoblasts to nanocrystalline silicon-substituted hydroxyapatite thin films.

Magnetron co-sputtering has been employed to fabricate thin nanocrystalline coatings of silicon-substituted hydroxyapatite (SiHA) of different Si compositions: 0.8 wt%, 2.2 wt%, and 4.9 wt%. A human osteoblast-like (HOB) cell model was used to study the long-term interaction between the HOB cells and coatings in vitro. Results showed that the number of cells growing on all coated titanium (Ti) samples were statistically significantly higher than on uncoated Ti. In addition, HOB cells growing on all SiHA surfaces displayed enhanced cell spreading, with extensive extracellular matrix synthesis. DNA staining revealed normal phenotype nuclear morphology for HOB cells, with several dense chromosomes surrounded by a periphery of intact nuclear membrane. Furthermore, immunofluorescent staining indicated that cells showed improved adhesion on the coated surfaces with increasing Si content, developing mature cytoskeletons with numerous distinct and well-defined actin stress fibres in the cell membranes. Results also demonstrated that the bone mineralisation process was greatest in the presence of the highest Si level (4.9 wt%). However, at very early culturing time point, cells did not attach so readily on the surface of this coating due to rapid dissolution. Thus, this work suggests that a Si content of 2.2 wt% may be the optimum loading to improve the bioactive property of HA thin films.

Cell Adhesion↗

The effectiveness of anti-tumor necrosis factor therapy in preventing progressive radiographic joint damage in rheumatoid arthritis: a population-based study.

OBJECTIVE: To compare the effectiveness of 3 therapeutic strategies in preventing progressive joint damage, in a population-based cohort. The 3 strategies were infliximab with concomitant disease-modifying antirheumatic drugs (DMARDs), etanercept with concomitant DMARDs, and etanercept alone. METHODS: We used sequential radiographs to assess all patients who were treated with infliximab or etanercept for >10 months. The rates of erosion progression and joint space narrowing (JSN) were analyzed using multivariate regression models for longitudinal data, with adjustment for potential confounders. RESULTS: A total of 372 patients treated with anti-tumor necrosis factor (TNF) therapies met the inclusion criteria. The baseline characteristics of the patients assigned to the 3 strategies were not significantly different, except that, as expected, more patients were receiving combination therapy with infliximab. The combination of infliximab plus DMARDs was significantly more effective than etanercept alone for controlling erosion progression (P < 0.001), but the effectiveness of the 2 combination-treatment strategies was similar (P = 0.07). The combination of infliximab plus DMARDs was also more effective at controlling progressive JSN compared with etanercept alone (P = 0.04) or etanercept plus DMARDs (P = 0.02). Treatment with anti-TNF agents (infliximab or etanercept) plus concomitant DMARDs was more effective than treatment with etanercept alone for controlling erosion progression (P = 0.045). CONCLUSION: When combined with traditional DMARDs, both etanercept and infliximab appear to offer similar protection against progressive structural joint damage, and combination therapy with either of these agents appears to be more effective than treatment with etanercept alone.

Adult↗

Early experiences with e-health services (1999-2002): promise, reality, and implications.

BACKGROUND: E-health services may improve the quality and efficiency of care; however, there is little quantitative data on e-health use. OBJECTIVE: The objective of this study was to examine trends in e-health use and user characteristics. RESEARCH DESIGN: This was a longitudinal study of e-health use (1999-2002) within an integrated delivery system (IDS). We classified 4 e-health services into transactional (drug refills and appointment scheduling) and care-related (medical and medication advice) services. SUBJECTS: Approximately 3.3 million members of a large, prepaid IDS. MEASUREMENTS: Amount and frequency of e-health use over time and characteristics of users. RESULTS: The number of members registered for access to e-health increased from 20,617 (0.7% of all members) in Q1 1999 to 270,987 (8.6%) in Q3 2002. Between Q1 and Q3 2002, 42,845 members (1.3%) used the drug refill service and 55,901 (1.7%) used the appointment scheduling service compared with 10,756 members (0.3%) who used the medical advice service and 3069 (0.1%) who used the medication advice service. Over the same period, transactional service users averaged 3.5 uses/user versus 1.6 uses/user among care-related service users. Members most likely to use e-health services had a high level of clinical need, a regular primary care provider, were 30 to 64 years old, female, white, and lived in a nonlow socioeconomic status neighborhood. These findings were consistent across e-health service types. CONCLUSIONS: Although use of all e-health services grew rapidly, use of care-related services lagged significantly behind use of transactional services. Subjects with greater clinical need and better ties to the health system were more likely to use both types of e-health services.

Adolescent↗

Inflammatory disease and lymphomagenesis caused by deletion of the Myc antagonist Mnt in T cells.

Mnt is a Max-interacting protein that can antagonize the activities of Myc oncoproteins in cultured cells. Mnt null mice die soon after birth, but conditional deletion of Mnt in breast epithelium leads to tumor formation. These and related data suggest that Mnt functions as a tumor suppressor. Here we show that conditional deletion of Mnt in T cells leads to tumor formation but also causes inflammatory disease. Deletion of Mnt caused increased apoptosis of thymic T cells and interfered with T-cell development yet led to spleen, liver, and lymph node enlargement. The proportion of T cells in the spleen and lymph nodes was reduced, and the numbers of cells in non-T-cell immune cell populations were elevated. The disruption of immune homeostasis is linked to a strong skewing toward production of T-helper 1 (Th1) cytokines and enhanced proliferation of activated Mnt-deficient CD4+ T cells. Consistent with Th1 polarization in vivo, extensive intestinal inflammation and liver necrosis developed. Finally, most mice lacking Mnt in T cells ultimately succumbed to T-cell lymphoma. These results strengthen the argument that Mnt functions as a tumor suppressor and reveal a critical and surprising role for Mnt in the regulation of T-cell development and in T-cell-dependent immune homeostasis.

Animals↗

MR imaging- versus conventional X-ray fluoroscopy-guided renal angioplasty in swine: prospective randomized comparison.

PURPOSE: To test the hypothesis that the technical success rates, complication rates, and procedural times for magnetic resonance (MR) imaging-guided percutaneous transluminal angioplasty (PTA) and conventional (x-ray) fluoroscopy-guided PTA for treatment of renal artery stenosis are similar. MATERIALS AND METHODS: The study was animal care and use committee approved. After surgically inducing bilateral renal artery stenosis in 11 swine, the authors performed baseline digital subtraction angiography. They transferred each animal to a 1.5-T MR imaging unit and randomly decided which artery would be treated with MR-guided PTA. With MR imaging guidance, angioplastic devices were tracked by using active and passive techniques. Vascular depiction was achieved by using catheter-directed MR angiography. Stenotic vessels were dilated by using 5-6-mm-diameter balloon catheters. PTA was then performed in the contralateral artery by using conventional fluoroscopy-guided techniques. With the intention to treat, the authors compared the technical success (residual stenosis < 50%) rates, complication rates, and procedural times for each guidance method. They compared technical successes and complications by using the McNemar test and procedural times by using a paired t test, with P < .05 indicating a significant difference. RESULTS: The authors successfully dilated nine (82%) of 11 renal arteries with MR guidance and all 11 arteries (100%) with conventional fluoroscopic guidance. The difference was not significant (P = .5). Complications occurred in three (27%) arteries with MR guidance and in one (9%) artery with fluoroscopic guidance, with no significant differences (P = .5). The mean MR-guided PTA procedural time was 46 minutes longer than the fluoroscopy-guided PTA procedural time; this difference was significant (P = .01). CONCLUSION: In a small cohort of swine, the authors did not observe a significant difference between MR imaging- and conventional fluoroscopy-guided renal artery PTA in terms of success and complication rates. However, no evidence of similarity between the techniques should be assumed. Procedural times differed significantly.

Angioplasty↗

[Prognostic value of N-terminal-pro-brain natriuretic peptide on admission in patients with chronic heart failure].

OBJECTIVE: Heart failure is responsible for a huge burden in hospital care. Our goal was to evaluate the value of N-terminal-pro-brain natriuretic peptide (Nt-proBNP) on predicting death or hospital readmission after hospital discharge in patients with chronic heart failure (CHF). METHODS: From March 2003 to April 2005, 135 consecutive patients (97 male and 38 female, mean age 60.7 years +/- 13.1 years) with chronic heart failure [dilated cardiomyopathy (44%) and coronary heart disease (35%)] were included in this study. Plasma concentrations of the Nt-proBNP were measured by ELISA on admission. All patients received conventional therapy and were followed up for 24 months. The primary end point was death or readmission. RESULTS: (1) During the follow up period (640 days +/- 100 days), 11 patients died and 39 patients rehospitalized, the median Nt-proBNP level on admission was significantly higher in patients died during the follow up period (5908 ng/L) than that of rehospitalized patients (2768 ng/L, P = 0.038). Plasma Nt-proBNP level on admission were significantly higher in primary end point group (n = 50, 2947 ng/L) than that in non-primary end point group (n = 85, 917 ng/L, P < 0.01). (2) Variables associated with an increased hazard of death and/or rehospitalization were Nt-proBNP and NYHA degree when analyzed by logistic regression models. Increased Log Nt-proBNP was the strongest independent predictor of an adverse outcome of CHF (odds ratio 13.8, 95% confidence interval 2.29 to 2.78, P < 0.01). (3) Area under the curve for Nt-proBNP in evaluating prognosis of CHF patients was 0.885 (positive predictive value 88.5%, negative predictive value 11.5%). CONCLUSION: Nt-proBNP level on admission is a strong predictor of rehospitalization and death within 24 months after hospital discharge in patients with chronic heart failure.

Adolescent↗

[Construction of multifunctonal nano-delivery system crossing blood brain barrier].

OBJECTIVE: To construct multifunctonal nano-delivery system crossing the blood brain barrier (BBB). METHODS: The magnetic nanoparticles were preprared with O-carboxylmethylated chitosan (O-CMC) and conjugated with a peptide sequence from the human immunodeficiency virus 1-tat protein and transferrin (Tf), and anti-tumor drug methotrexate (MTX), and thus constructed a O-CMC magnetic nanoparticles carrier system conjugating with Tat and Tf (O-MNPs-Tat-Tf) that combines multiple functions including crossing BBB, magnetism, receptor-mediated dual targets and anti-tumor capabilities. The appearance, diameter, and magnetism of MTX-O-MNPs-Tat-Tf carrier system were characterized with transmission electronic microscopy, atomic force microscopy and vibrating samples magnetometer. The cytotoxicity of MTX-loaded O-MNPs-Tat-Tf was investigated with C6 glioma cells. The ability of O-MNPs-Tat-Tf crossing BBB was investigated in rats by single photon emission computed tomography. RESULTS: The mean particle diameter was 75 nm, along with good anti-tumor property. The multi-functioned carrier system successfully crossed the BBB in rat. CONCLUSION: The establishment of MTX-O-MNPs-Tat-Tf carrier model implies a promising future for its application in therapy of cerebral diseases.

Blood-Brain Barrier↗

Vdelta1 T cell receptor binds specifically to MHC I chain related A: molecular and biochemical evidences.

Human MHC class I chain-related A (MICA) is a tumor-associated antigen that can be recognized by Vdelta1 subset of tumor-infiltrating gammadelta T cells. We previously reported that immobilized recombinant MICA protein could induce the proliferation of tumor-infiltrating Vdelta1 gammadelta T cells in vitro. But there has been no direct evidence showing the engagement of gammadelta T cell receptors (TCR) of the induced cells with MICA. In the current investigation, we show that MICA induces specific cytolytic activity of the expanded gammadelta T cells. We expressed the coupled V domains from the MICA-induced T cells as a single polypeptide chain Vdelta Vgamma TCR (gammadelta scTCR). Such scTCR can specifically bind MICA of HeLa cells. Direct interaction of gammadelta scTCRs with in vitro expressed MICA was monitored using an IAsys biosensor. We found that the Vdelta1 scTCR can specifically bind to immobilized MICA molecule and MICA alpha1alpha2 domains are responsible for the binding reaction.

Antibodies, Monoclonal↗

Disruption of microtubules ablates the specificity of insulin signaling to GLUT4 translocation in 3T3-L1 adipocytes.

Although the cytoskeletal network is important for insulin-induced glucose uptake, several studies have assessed the effects of microtubule disruption on glucose transport with divergent results. Here, we investigated the effects of microtubule-depolymerizing reagent, nocodazole and colchicine, on GLUT4 translocation in 3T3-L1 adipocytes. After nocodazole treatment to disrupt microtubules, GLUT4 vesicles were dispersed from the perinuclear region in the basal state, and insulin-induced GLUT4 translocation was partially inhibited by 20-30%, consistent with other reports. We found that platelet-derived growth factor (PDGF), which did not stimulate GLUT4 translocation in intact cells, was surprisingly able to enhance GLUT4 translocation to approximately 50% of the maximal insulin response, in nocodazole-treated cells with disrupted microtubules. This effect of PDGF was blocked by pretreatment with wortmannin and attenuated in cells pretreated with cytochalasin D. Using confocal microscopy, we found an increased co-localization of GLUT4 and F-actin in nocodazole-treated cells upon PDGF stimulation compared with control cells. Furthermore, microinjection of small interfering RNA targeting the actin-based motor Myo1c, but not the microtubule-based motor KIF3, significantly inhibited both insulin- and PDGF-stimulated GLUT4 translocation after nocodazole treatment. In summary, our data suggest that 1) proper perinuclear localization of GLUT4 vesicles is a requirement for insulin-specific stimulation of GLUT4 translocation, and 2) nocodazole treatment disperses GLUT4 vesicles from the perinuclear region allowing them to engage insulin and PDGF-sensitive actin filaments, which can participate in GLUT4 translocation in a phosphatidylinositol 3-kinase-dependent manner.

3T3-L1 Cells↗