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1.
J Immunol Res ; 2022: 7267131, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35846428

RESUMEN

Hepatocellular carcinoma (HCC) remains an incurable disease with a very poor clinical outcome. The purpose of this article was to investigate whether the expression or methylation of tetrapeptide repeat domain 36 (TTC36) could be used as a prognostic marker in hepatocellular carcinoma. TCGA database was used to obtain information on HCC gene expression and the associated clinical features of HCC patients. Differentially expressed genes (DEGs) were screened between 374 HCC specimens and 50 nontumor specimens. The expression and prognostic value of TTC36 were analyzed. The correlations between TTC36 and cancer immune infiltrates were investigated via TIMER. In this study, HCC specimens and nontumor specimens were compared and 35 DEGs were found between them. Among the 35 DEGs, the expression of TTC36 was significantly reduced in HCC samples compared with nontumor samples. Survival tests revealed that patients with low TTC36 expression had a shorter overall survival than patients with high TTC36 expression. TTC36 was found to be an independent predictive factor for HCC in both univariate and multivariate regression analyses. TTC36 was negatively regulated by TTC36 methylation, leading to its low expression in HCC tissues. Immune analysis revealed that TTC36 expression has significant correlations with B cell, T cell CD4+, neutrophil, macrophage, and myeloid dendritic cell. Finally, TTC36 expression was dramatically reduced in HCC cells, and overexpression greatly suppressed HCC cell proliferation and invasion, according to our experimental results. Overall, our data suggested that TTC36 could be applied as a prognostic marker for predicting outcome and immune infiltration in HCC.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Biomarcadores de Tumor/metabolismo , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Metilación , Pronóstico
2.
Int J Nanomedicine ; 16: 4631-4642, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34262273

RESUMEN

PURPOSE: Antibiotic-resistant bacteria are pathogens that have emerged as a serious public health risk. Thus, there is an urgent need to develop a new generation of anti-bacterial materials to kill antibiotic-resistant bacteria. METHODS: Nanosilver-decorated mesoporous organosilica nanoparticles (Ag-MONs) were fabricated for co-delivery of gentamicin (GEN) and nanosilver. After investigating the glutathione (GSH)-responsive matrix degradation and controlled release of both GEN and silver ions, the anti-bacterial activities of Ag-MONs@GEN were systematically determined against several antibiotic-susceptible and antibiotic-resistant bacteria including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis. Furthermore, the cytotoxic profiles of Ag-MONs@GEN were evaluated. RESULTS: The GEN-loaded nanoplatform (Ag-MONs@GEN) showed glutathione-responsive matrix degradation, resulting in the simultaneous controlled release of GEN and silver ions. Ag-MONs@GEN exhibited excellent anti-bacterial activities than Ag-MONs and GEN alone via inducing ROS generation, especially enhancing synergetic effects against four antibiotic-resistant bacteria including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis. Moreover, the IC50 values of Ag-MONs@GEN in L929 and HUVECs cells were 313.6 ± 15.9 and 295.7 ± 12.3 µg/mL, respectively, which were much higher than their corresponding minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. CONCLUSION: Our study advanced the development of Ag-MONs@GEN for the synergistic and safe treatment of antibiotic-resistant bacteria.


Asunto(s)
Farmacorresistencia Microbiana/efectos de los fármacos , Gentamicinas/farmacología , Glutatión/química , Nanopartículas/química , Dióxido de Silicio/química , Plata/química , Animales , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Liberación de Fármacos , Sinergismo Farmacológico , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Ratones , Pruebas de Sensibilidad Microbiana , Nanopartículas/ultraestructura
3.
Acta Neurochir (Wien) ; 163(9): 2603-2614, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34291383

RESUMEN

BACKGROUND: Hyperosmotic therapy is a mainstay treatment for cerebral edema. Although often effective, its disadvantages include mainly acting on the normal brain region with limited effectiveness in eliminating excess fluid in the edema region. This study investigates how to configure our previously proposed novel electroosmosis based edema treatment as a complement to hyperosmotic therapy. METHODS: Three electrode configurations are designed to drive the excess fluid out of the edema region, including 2-electrode, 3-electrode, and 5-electrode designs. The focality and directionality of the induced electroosmotic flow (EOF) are then investigated using the same patient-specific head model with localized edema. RESULTS: The 5-electrode design shows improved EOF focality with reduced effect on the normal brain region than the other two designs. Importantly, this design also achieves better directionality driving excess edema tissue fluid to a larger region of surrounding normal brain where hyperosmotic therapy functions better. Thus, the 5-electrode design is suggested to treat edema more efficiently via a synergic effect: the excess fluid is first driven out from the edema to surrounding normal brain via EOF, where it can then be treated with hyperosmotic therapy. Meanwhile, the 5-electrode design drives 2.22 mL excess fluid from the edema region in an hour comparable to the other designs, indicating a similar efficiency of EOF. CONCLUSIONS: The results show that the promise of our previously proposed novel electroosmosis based edema treatment can be designed to achieve better focality and directionality towards a complement to hyperosmotic therapy.


Asunto(s)
Edema Encefálico , Electroósmosis , Encéfalo , Edema Encefálico/terapia , Edema , Electrodos , Humanos
4.
J Mech Behav Biomed Mater ; 112: 103982, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32829165

RESUMEN

Porous fusion cage is considered as a satisfactory substitute for solid fusion cage in transforaminal lumbar interbody fusion (TLIF) surgery due to its interconnectivity for bone ingrowth and appropriate stiffness reducing the risk of cage subsidence and stress shielding. This study presents an integrated global-local topology optimization approach to obtain porous titanium (Ti) fusion cage with desired biomechanical properties. Local topology optimizations are first conducted to obtain unit cells, and the numerical homogenization method is used to quantified the mechanical properties of unit cells. The preferred porous structure is then fabricated using selective laser melting, and its mechanical property is further verified via compression tests and numerical simulation. Afterward, global topology optimization is used for the global layout. The porous fusion cage obtained by the Boolean intersection between global structural layout and the porous structure decreases the solid volume of the cage by 9% for packing more bone grafts while achieving the same stiffness to conventional porous fusion cage. To eliminate stress concentration in the thin-wall structure, framework structures are constructed on the porous fusion cage. Although the alleviation of cage subsidence and stress shielding is decelerated, peak stress on the cage is significantly decreased, and more even stress distribution is demonstrated in the reinforced porous fusion cage. It promises long-term integrity and functions of the fusion cage. Overall, the reinforced porous fusion cage achieves a favorable mechanical performance and is a promising candidate for fusion surgery. The proposed optimization approach is promising for fusion cage design and can be extended to other orthopedic implant designs.


Asunto(s)
Trasplante Óseo , Simulación por Computador , Fusión Vertebral , Fenómenos Biomecánicos , Vértebras Lumbares , Porosidad
5.
Diagn Microbiol Infect Dis ; 96(2): 114956, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31813640

RESUMEN

Two linezolid-resistant and teicoplanin-intermediate Staphylococcus epidermidis strains were isolated from blood cultures in China. The 2 S. epidermidis strains were methicillin-resistant and showed multidrug-resistance patterns; in addition, population analysis profiling/area under the curve (PAP/AUC) result showed heterogeneous resistant to vancomycin. Comparing to teicoplanin susceptible strains, the 2 isolates showed reduced autolytic activity. Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) indicated that the 2 S. epidermidis isolates belonged to the same clone. Furthermore, the cfr gene, a G2576T mutation, and a novel C2146T mutation were detected in the 2 isolates. This was the first report of S. epidermidis simultaneously nonsusceptible to linezolid and teicoplanin in China.


Asunto(s)
Antibacterianos/farmacología , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/microbiología , Linezolid/farmacología , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Staphylococcus epidermidis/efectos de los fármacos , Teicoplanina/farmacología , Adulto , Alelos , China/epidemiología , Femenino , Genes Bacterianos , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Tipificación de Secuencias Multilocus , Mutación , Staphylococcus epidermidis/genética
6.
Cell Physiol Biochem ; 48(1): 111-119, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30001552

RESUMEN

BACKGROUND/AIMS: CD24 is a highly glycosylated mucin-like antigen on the cell surface, which has recently emerged as a novel oncogene and metastasis promoter. We performed bioinformatics analysis to investigate whether CD24 can serve as a prognostic indicator in breast cancer. METHODS: CD24 expression was assessed using SAGE Genie tools and Oncomine analysis. The PrognoScan database, Kaplan-Meier Plotter, and bc-GenExMiner were used to identify the prognostic roles of CD24 in breast cancer. RESULTS: We found that CD24 was more frequently overexpressed in breast cancer than in normal breast tissue and correlated with worse prognosis. Meanwhile, high CD24 expression was associated with increased risk of HER2, basal-like, triple-negative breast cancer, and higher Scarff-Bloom-Richardson grade. Data mining in multiple big databases confirmed a positive correlation between CD24 mRNA expression and SDC1 mRNA expression in breast cancer tissue. CONCLUSIONS: Our findings suggest that CD24 overexpression is more common in breast cancer than in corresponding normal tissue. In addition, CD24 and SDC1 can serve as prognostic indicators for breast cancer. However, large-scale and comprehensive research is needed to further confirm these results.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/diagnóstico , Antígeno CD24/metabolismo , Biomarcadores de Tumor/genética , Mama/metabolismo , Mama/patología , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/mortalidad , Antígeno CD24/genética , Bases de Datos Factuales , Supervivencia sin Enfermedad , Femenino , Humanos , Estimación de Kaplan-Meier , Persona de Mediana Edad , Pronóstico , Modelos de Riesgos Proporcionales , ARN Mensajero/metabolismo , Factores de Riesgo , Sindecano-1/genética , Sindecano-1/metabolismo , Neoplasias de la Mama Triple Negativas/diagnóstico , Neoplasias de la Mama Triple Negativas/metabolismo
7.
Pathol Res Pract ; 214(3): 327-334, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29487006

RESUMEN

OBJECTIVE: Thyroid cancer (TC) is the most common malignant endocrine-related cancer with an increasing trend worldwide. Therefore, it's in urgent need to find new markers for prognosis and diagnosis. Many long noncoding RNAs (lncRNAs) have been reported to be aberrantly expressed in TC, and may serve as biomarkers. Therefore, we performed this meta-analysis to systematically summarize the relationship between lncRNA expressions and TC. METHODS: Sources from PubMed, Embase and Web of Science were searched. A total of 16 eligible studies including 15 on clinicopahology, 5 on prognosis and 6 on diagnosis were enrolled in our meta-analysis. Revman5.3 and Stata11.0 Software were used to conduct the meta-analysis. RESULTS: For diagnostic value, lncRNAs could discriminate between TC and the normal, and yield a high overall sensitivity and specificity (0.80, 95% CI: 0.75-0.84; 0.80, 95% CI: 0.70-0.87). Meanwhile, their sensitivity and specificity were 0.74 (95% CI: 0.59-0.85) and 0.81 (95% CI: 0.73-0.88) respectively, when used to differentiate patients with lymph node metastasis (LNM) from without LNM. The summary receiver operator characteristic curve (sROC) showed that lncRNAs could be considered as valuable diagnostic markers for distinguishing TC patients from the normal (AUC = 0.84) and TC patients with LNM from TC patients without LNM (AUC = 0.85). CONCLUSIONS: In summary, our meta-analysis suggested that lncRNAs could function as potential diagnostic markers for TC and predict the LNM. In addition, the systematic review elaborated that lncRNAs might be as prognostic indicators in TC.


Asunto(s)
Regulación Neoplásica de la Expresión Génica/genética , Metástasis Linfática/diagnóstico , ARN Largo no Codificante/genética , Neoplasias de la Tiroides/diagnóstico , Animales , Biomarcadores de Tumor/metabolismo , Humanos , Metástasis Linfática/genética , Pronóstico , Neoplasias de la Tiroides/genética
8.
Cancer Biol Ther ; 17(6): 684-92, 2016 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-27224726

RESUMEN

Transmembrane tumor necrosis factor-α (tmTNF-α) is known to induce the activation of NF-κB to protect tumor cells. Upregulation of tmTNF-α leads to resistance to apoptosis and induces drug resistance in breast cancer. However, the expression of tmTNF-α in colorectal cancer (CRC) and its association with clinical outcome in CRC have remained unclear. In this study, we examined the tmTNF-α expression in CRC by immunohistochemistry and western blotting, assessed the prognostic value of tmTNF-α related to the recurrence/metastasis and survival of stage II/III CRC by the Kaplan-Meier survival curve and Cox regression model, and also explored the role of tmTNF-α expression on the chemotherapeutic efficacy of 5-Fluorouracil by flow cytometry assay and cell counting kit-8 (CCK-8) in vitro. Overall, we found that 77 (78.6%) out of 98 patients exhibited higher tmTNF-α expression in the CRC tissues comparing with the adjacent tissues. The tmTNF-α expression was correlated with Differentiation (P = 0.019), TNM stage (P = 0.039), Lymph nodes metastasis (P = 0.024) and Lymphovascular invasion (P = 0.027) but not related with Age (P = 0.617), Gender (P = 0.625), Tumor location (P = 0.138), Perforation/Obstruction (P = 1.000), Depth of invasion (P = 0.327), and microsatellite instability status (P = 0.150). The prognostic analyses showed that high tmTNF-α expression patients was significantly associated with decreased Disease-Free Survival (P = 0.0209) and Overall Survival (P = 0.0163). CCK-8 results suggested that the tmTNF-α influenced the chemotherapeutic effect of 5-Fluorouracil on colon cancer cells. Altogether, these data indicated the stageII/III CRC patients with high tmTNF-α expression were more likely to have a worse prognosis than patients with low tmTNF-α expression and tmTNF-α may influence the chemotherapeutic effect of 5-Fluorouracil. The mechanism for these observations warrants further study.


Asunto(s)
Neoplasias Colorrectales/tratamiento farmacológico , Factor de Necrosis Tumoral alfa/farmacología , Quimioterapia Adyuvante , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Femenino , Fluorouracilo/farmacología , Humanos , Masculino , Pronóstico , Transducción de Señal , Análisis de Supervivencia
9.
Acta Neurochir (Wien) ; 157(4): 639-48; discussion 648, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25686919

RESUMEN

BACKGROUND: Cytotoxic brain tissue edema is a complicated secondary consequence of ischemic injury following cerebral diseases such as traumatic brain injury and stroke. To some extent the pathophysiological mechanisms are known, but far from completely. In this study, a hypothesis is proposed in which protein unfolding and perturbation of nucleotide structures participate in the development of cytotoxic edema following traumatic brain injury (TBI). METHODS: An advanced computational simulation model of the human head was used to simulate TBI. The consequences of kinetic energy transfer following an external dynamic impact were analyzed including the intracranial pressure (ICP), strain level, and their potential influences on the noncovalent and covalent bonds in folded protein structures. RESULTS: The result shows that although most of the transferred kinetic energy is absorbed in the skin and three bone layers, there is a substantial amount of energy reaching the gray and white matter. The kinetic energy from an external dynamic impact has the theoretical potential to interfere not only with noncovalent but also covalent bonds when high enough. The induced mechanical strain and pressure may further interfere with the proteins, which accumulate water molecules into the interior of the hydrophobic structures of unfolded proteins. Simultaneously, the noncovalent energy-rich bonds in nucleotide adenosine-triphosphates may be perturbed as well. CONCLUSIONS: Based on the analysis of the numerical simulation data, the kinetic energy from an external dynamic impact has the theoretical potential to interfere not only with noncovalent, but also with covalent bonds when high enough. The subsequent attraction of increased water molecules into the unfolded protein structures and disruption of adenosine-triphosphate bonds could to some extent explain the etiology to cytotoxic edema.


Asunto(s)
Edema Encefálico/etiología , Lesiones Encefálicas/complicaciones , Encéfalo/fisiopatología , Simulación por Computador , Cabeza , Modelos Anatómicos , Edema Encefálico/fisiopatología , Lesiones Encefálicas/fisiopatología , Humanos , Presión Intracraneal
10.
Asian Pac J Cancer Prev ; 15(7): 3299-304, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24815486

RESUMEN

BACKGROUND: The aim of the present study was to analyze whether Homer1 is a potential prognostic marker for intrahepatic cholangiocarcinoma (ICC). MATERIALS AND METHODS: The expression of Homer1 in ICC tissue was detected with immunohistochemistry and levels of protein in ICC and paratumor tissues were evaluated by Western blotting. Survival analysis by the Kaplan-Meier method was performed to assess prognostic significance. RESULTS: Homer1 expression was high in 67.4% (58/86) of ICC samples, and there was significant difference between ICC and adjacent noncancerous tissues (p<0.001); high expression was associated with poor histologic differentiation (p=0.019), TNM stage (p=0.014), lymph node metastasis (p=0.040), and lymphatic invasion (p=0.025). On Kaplan-Meier analysis, a comparison of survival curves of low versus high expressors of Homer1 revealed a highly significant difference in OS (p=0.001) and DFS (p=0.006), indicating that high expression of Homer1 was linked with a worse prognosis. Multivariate analyses showed that Homer1 expression was an independent risk factor predicting overall survival[Hazard ratio(HR), 7.52; 95% confidence interval (CI), 2.63- 21.47; p=0.002] and disease-free survival (HR, 11.56; 95%CI, 5.17-25.96; p<0.001) in ICC. CONCLUSIONS: Homer1 promotes lymphatic invasion and associates with lymph node metastasis and poor prognosis of ICC. The current study shows that Homer1 may be an independent prognostic factor for ICC patients after curative resection, and it provides an important basis for screening/treating high-risk patients.


Asunto(s)
Neoplasias de los Conductos Biliares/genética , Neoplasias de los Conductos Biliares/patología , Conductos Biliares Intrahepáticos/patología , Proteínas Portadoras/genética , Colangiocarcinoma/genética , Colangiocarcinoma/patología , Adulto , Anciano , Neoplasias de los Conductos Biliares/mortalidad , Proteínas Portadoras/biosíntesis , Colangiocarcinoma/mortalidad , Supervivencia sin Enfermedad , Femenino , Proteínas de Andamiaje Homer , Humanos , Estimación de Kaplan-Meier , Metástasis Linfática/genética , Metástasis Linfática/patología , Masculino , Persona de Mediana Edad , Análisis Multivariante , Invasividad Neoplásica/genética , Estadificación de Neoplasias , Análisis de Supervivencia
11.
Hepatogastroenterology ; 60(126): 1519-23, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23933945

RESUMEN

BACKGROUND/AIMS: To investigate the expression of human epidermal growth factor 2 (HER-2) and Nuclear factor-Kb (NF-KB) in gastric cancer, and the relation of these two parameters with stage, grade and metastasis of gastric cancer. METHODOLOGY: The serum level of HER-2 in 75 gastric cancer patients and control participants were determined by enzyme-linked immunosorbent assay (ELISA) kits. Expression of HER-2 and NF-KB protein were detected by immunohistochemical staining (SP method) of paraffin-embedded tissues in 75 tumors (observed group) and 22 normal gastric specimens. The clinical pathological data was statistically analyzed. RESULTS: Serum HER-2 level were significantly increased in study group compared with those in the control group (p<0.001). The HER-2 level of 8.2 ng/mL as the cutoff value has a 79% sensitivity and an 82% specificity for predicting gastric cancer. The positive rate of HER-2 and NF-KB in the observed group was 24.00% (18/75) and 62.67% (47/75) respectively. The expression of HER-2 and NF-KB were not correlated with age and gender, but with stage, grade and metastasis (p<0.05). The expression of NF-KB was correlated with tumor size (p<0.05), while HER-2 was not (p<0.05). When HER-2 was positive, N F-KB had a positive rate of 94.44% (17/18), but a positive rate of 52.63% (30/57) when HER-2 was negative. Expression of NF-KB in gastric cancer tissue was correlated with HER-2 expression (X2 = 8.514, p<0.01). CONCLUSIONS: These data suggest that the expression of NF-KB in gastric cancer tissue is correlated with HER-2 expression, and they may play a very important role in the progress of gastric cancer.


Asunto(s)
FN-kappa B/análisis , Receptor ErbB-2/análisis , Neoplasias Gástricas/química , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Mucosa Gástrica/química , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Neoplasias Gástricas/patología
12.
Hepatogastroenterology ; 60(126): 1333-42, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23340167

RESUMEN

BACKGROUND/AIMS: It remains a question whether anti-TNF-a treatment is associated with an increase of serious adverse events (SAE) in Crohn's Disease (CD) patients. This study aims to assess the risk of SAE of anti-TNF-a treatment in CD patients. METHODOLOGY: Literature search of EMBASE, PubMed, ScienceDirect, Cochrane Library and ClinicalTrials.gov until June 2012 was conducted. Eligible studies were randomized controlled trials (RCTs) ofTNF-a inhibitors treated for at least 24 weeks in CD patients. RESULTS: Thirteen RCTs, involving 4,257 patients with CD were included in analysis. SAE were reported in 364 patients (14.26%) in treatment groups and 263 patients (15.43%) in control groups. The proportion of patients with SAE was lower with TNF-a inhibitors than with placebo (OR, 0.80; 95% CI, 0.67-0.96; p=0.01). Compared with controls, the risks of malignancy and serious infection treated with TNF-a inhibitors showed no significant difference (p>0.05). CONCLUSIONS: In CD patients, anti-TNF-a treatment, especially for adalimumab, could decrease the incidence of SAE, without an increased risk of malignancy or serious infection. TNF-a inhibitors are safe in treatment of CD patients. To assess the risk of SAE, larger samples of randomized control trials with long term follow-up are needed.


Asunto(s)
Enfermedad de Crohn/tratamiento farmacológico , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Adalimumab , Anticuerpos Monoclonales/efectos adversos , Anticuerpos Monoclonales Humanizados/efectos adversos , Humanos , Infecciones/inducido químicamente , Infliximab , Linfoma/inducido químicamente , Ensayos Clínicos Controlados Aleatorios como Asunto
13.
J Biol Chem ; 287(9): 6551-61, 2012 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-22174419

RESUMEN

Pkd2L1 (also called TRPP3) is a non-selective cation channel permeable to Ca(2+), Na(+), and K(+) and is activated by Ca(2+). It is also part of an acid-triggered off-response cation channel complex. We previously reported roles of the Pkd2L1 C-terminal fragments in its channel function, but the role of the N terminus remains unclear. Using a yeast two-hybrid screening, we found that the Pkd2L1 N terminus interacts with the receptor for activated C kinase 1 (RACK1), a scaffolding/anchoring protein implicated in various cellular functions. This interaction requires the last two Trp-Asp (WD) motifs of RACK1 and fragment Ala(19)-Pro(45) of Pkd2L1. The interaction was confirmed by GST pulldown, blot overlay, and co-immunoprecipitation assays. By (45)Ca tracer uptake and two-microelectrode voltage clamp electrophysiology, we found that in Xenopus oocytes with RACK1 overexpression Pkd2L1 channel activity is abolished or substantially reduced. Combining with oocyte surface biotinylation experiments, we demonstrated that RACK1 inhibits the function of Pkd2L1 channel on the plasma membrane in addition to reducing its total and plasma membrane expression. Overexpressing Pkd2L1 N- or C-terminal fragments as potential blocking peptides for the Pkd2L1-RACK1 interaction, we found that Pkd2L1 N-terminal fragment Met(1)-Pro(45), but not Ile(40)-Ile(97) or C-terminal fragments, abolishes the inhibition of Pkd2L1 channel by overexpressed and oocyte-native RACK1 likely through disrupting the Pkd2L1-RACK1 association. Taken together, our study demonstrated that RACK1 inhibits Pkd2L1 channel function through binding to domain Met(1)-Pro(45) of Pkd2L1. Thus, Pkd2L1 is a novel target channel whose function is regulated by the versatile scaffolding protein RACK1.


Asunto(s)
Canales de Calcio/química , Canales de Calcio/fisiología , Proteínas de Unión al GTP/química , Proteínas de Unión al GTP/fisiología , Proteínas de Neoplasias/química , Proteínas de Neoplasias/fisiología , Receptores de Superficie Celular/química , Receptores de Superficie Celular/fisiología , Animales , Sitios de Unión/fisiología , Calcio/metabolismo , Canales de Calcio/genética , Proteínas de Unión al GTP/genética , Células HEK293 , Humanos , Mutagénesis/fisiología , Proteínas de Neoplasias/genética , Oocitos/fisiología , Técnicas de Placa-Clamp , Dominios y Motivos de Interacción de Proteínas/fisiología , Estructura Terciaria de Proteína/fisiología , ARN Mensajero/farmacología , Receptores de Cinasa C Activada , Receptores de Superficie Celular/genética , Técnicas del Sistema de Dos Híbridos , Xenopus
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