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1.
Eur J Neurosci ; 56(2): 3786-3805, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35441400

RESUMEN

Ischaemic stroke (IS) is a cerebrovascular disease caused by cerebral infarction and cerebral artery occlusion. In this study, we proposed that EVs from bone marrow stromal cells (BMSCs) could reduce the impact of stroke by reducing the resultant glial cell activation and blood-brain barrier (BBB) leak. We furthermore investigated some of the signalling mechanisms. The transient middle cerebral artery occlusion (t-MCAO) mouse model was established. The behavioural deficits and neuronal damage were verified using Bederson's scale and the 28-point neurological score. The area of cerebral infarction was detected. The expressions of astrocytes/microglia markers and BBB permeability were evaluated by 2,3,5-triphenyltetrazolium chloride (TTC) staining. The internalization of EVs by astrocytes/microglia in the peripheral area was detected by fluorescence labelling. The expressions of astrocyte/microglia markers were measured by RT-qPCR. Levels of TNF-α and IL-1ß in microglia were detected by ELISA. BBB permeability was evaluated. The downstream target genes and pathway of miR-124 were analysed. Microglia/astrocytes were treated by oxygen-glucose deprivation reoxygenation (OGD/R). OGD/R microglia/astrocyte conditioned medium was used to culture bEnd.3 cells. The transendothelial electric resistance (TEER) of bEnd.3 cells was measured, and BBB permeability was characterized. Our results suggested that EVs from BMSCs can indeed reduce the extent of stroke-mediated damage and evidenced that these effects are mediated via expression of the non-coding RNA, miR-124 that may act via the peroxiredoxin 1 (PRX1). Our results provided further motivation to pursue the use of modified EVs as a treatment option for neurological diseases.


Asunto(s)
Isquemia Encefálica , Vesículas Extracelulares , Células Madre Mesenquimatosas , MicroARNs , Peroxirredoxinas , Accidente Cerebrovascular , Animales , Astrocitos/metabolismo , Barrera Hematoencefálica/metabolismo , Isquemia Encefálica/metabolismo , Células Endoteliales/metabolismo , Vesículas Extracelulares/metabolismo , Glucosa/metabolismo , Proteínas de Homeodominio , Infarto de la Arteria Cerebral Media/metabolismo , Células Madre Mesenquimatosas/metabolismo , Ratones , MicroARNs/genética , MicroARNs/metabolismo , Oxígeno/metabolismo , Permeabilidad , Peroxirredoxinas/metabolismo , Accidente Cerebrovascular/metabolismo
2.
J Integr Neurosci ; 21(3): 94, 2022 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-35633175

RESUMEN

BACKGROUND: Acute ischemic stroke (AIS) is the main cause of worldwide death and disability. Early neurological deterioration (END) can further increase the probability of death and disability in patients with ischemic stroke. Therefore, it is essential to find biomarkers to predict END early. Inflammatory response plays a crucial role in determining the course, outcome, and prognosis of END. Earlier studies focused on the relationship between routine hematological inflammatory markers and END, which limited the results. At present, relatively new and comprehensive markers of inflammatory response are relatively scarce. In this study, we investigate the predictive value of inflammatory markers in acute ischemic stroke cases for END which include systemic inflammatory response index (SIRI), platelet/lymphocyte ratio (PLR), lymphocyte/monocyte ratio (LMR), neutrophil/lymphocyte ratio (NLR), and then to establish a nomogram model. METHODS: A total of 375 patients with AIS were analyzed who were admitted to the Second Affiliated Hospital of Harbin Medical University from September 2019 to June 2021. The associations between END and inflammatory markers were studied by employing the analysis of univariate. Following that, through regression models of the least absolute shrinkage and selection operator, the END risk model's feature selection was optimized. The development of the model of prediction was carried out by applying the multivariable logistic regression analysis. The calibration, discrimination, and clinical efficacy of the prediction model were studied via calibration plot, C-index, and decision curve analysis (DCA). The bootstrapping validation method was used for the evaluation of internal validation. RESULTS: We constructed a nomogram consisting of CRP, monocytes, NIHSS and SIRI. This model had desirable calibration and discrimination, with a C-index of 0.757 (95% confidence interval: 0.702-0.805). Interval validation could still achieve the higher C-index value of 0.747. When the risk threshold for END was greater than 13% but less than 84%, DCA proved to be clinically useful. CONCLUSIONS: Our research shows that SIRI can be used as a new predictor of END, as well as a monitor of treatment response. Compared with the traditional single inflammatory indicator, the integration of SIRI nomogram can predict the occurrence of END more objectively and reliably.


Asunto(s)
Accidente Cerebrovascular Isquémico , Biomarcadores , Humanos , Accidente Cerebrovascular Isquémico/complicaciones , Accidente Cerebrovascular Isquémico/diagnóstico , Neutrófilos , Nomogramas , Pronóstico
3.
J Biochem Mol Toxicol ; 35(5): e22724, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33491845

RESUMEN

Increasing studies have indicated that abnormal expressed long noncoding RNAs (lncRNAs) play a vital role in ischemic stroke. Small nucleolar RNA host gene 8 (Snhg8), a member of lncRNAs, has been found to induce neuronal apoptosis in chronic cerebral ischemia models. Here, we aim to explore the function and molecular mechanism of Snhg8 in modulating microglial inflammation as well as brain microvascular endothelial cell (BMEC) damage following ischemic injury. Our data suggested that Snhg8 was low-expressed in the brain tissues of mice that underwent middle cerebral artery occlusion (MCAO) surgery and oxygen-glucose deprivation (OGD)-treated primary microglia and BMECs. Gain- or loss-of function approaches found that Snhg8 upregulation not only attenuated ischemic induced inflammatory response in microglia but also relieved BMECs injury both in vitro and in vivo. Furthermore, we conducted a bioinformatics analysis to explore the underlying mechanism of Snhg8. The results indicated that Snhg8 served as a competitive endogenous RNA by sponging miR-425-5p, which was proved to promote microglial inflammation and BMECs injury by targeting sirtuin1 (SIRT1)-mediated nuclear factor-κB (NF-κB) pathway. Overall, these results revealed that the Snhg8/miR-425-5p/SIRT1/NF-κB axis plays a critical role in the regulation of cerebral ischemia-induced microglial inflammation and brain-blood barrier damage.


Asunto(s)
Barrera Hematoencefálica/metabolismo , Accidente Cerebrovascular Isquémico/metabolismo , MicroARNs/metabolismo , Microglía/metabolismo , FN-kappa B/metabolismo , ARN Largo no Codificante/metabolismo , Transducción de Señal , Sirtuina 1/metabolismo , Animales , Barrera Hematoencefálica/lesiones , Barrera Hematoencefálica/patología , Accidente Cerebrovascular Isquémico/patología , Masculino , Ratones , Microglía/patología
4.
Inorg Chem ; 57(7): 3893-3902, 2018 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-29561147

RESUMEN

To provide deep insight into cation-cation interactions (CCIs) involving hexavalent actinyl species that are major components in spent nuclear fuel and pose important implications for the effective removal of radiotoxic pollutants in the environment, a series of homo- and heterobimetallic actinide complexes supported by cyclopentadienyl (Cp) and polypyrrolic macrocycle (H4L) ligands were systematically investigated using relativistic density functional theory. The metal sort in both parts of (THF)(H2L)(OAnVIO) and (An')IIICp3 from U to Np to Pu, as well as the substituent bonding to Cp from electron-donating Me to H to electron-withdrawing Cl, SiH3, and SiMe3, was changed. Over 0.70 electrons are unraveled to transfer from the electron-rich UIII to the electron-deficient AnVI of the actinyl moiety, leading to a more stable AnV-UIV isomer; in contrast, uranylneptunium and uranylplutonium complexes behave as electron-resonance structures between VI-III and V-IV. These were further corroborated by geometrical and electronic structures. The energies of CCIs (i.e., Oexo-An' bonds) were calculated to be -19.6 to -41.2 kcal/mol, affording those of OUO-Np (-23.9 kcal/mol) and OUO-Pu (-19.6 kcal/mol) with less electron transfer (ET) right at the low limit. Topological analyses of the electron density at the Oexo-An' bond critical points demonstrate that the CCIs are ET or dative bonds in nature. A positive correlation has been built between the CCIs' strength and corresponding ET amount. It is concluded that the CCIs of Oexo-An' are driven by the electrostatic attraction between the actinyl oxo atom (negative) and the actinide ion (positive) and enhanced by their ET. Finally, experimental syntheses of (THF)(H2L)(OUVIO)(An')IIICp3 (An' = U and Np) were well reproduced by thermodynamic calculations that yielded negative free energies in a tetrahydrofuran solution but a positive one for their uranylplutonium analogue, which was synthetically inaccessible. So, our thermodynamics would provide implications for the synthetic possibility of other theoretically designed bimetallic actinide complexes.

5.
Adv Clin Exp Med ; 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38860714

RESUMEN

BACKGROUND: Acute kidney injury (AKI) has become a common complication of acute ischemic stroke (AIS) and may have a significant impact on clinical outcomes. Anion gap (AG)/albumin corrected anion gap (ACAG) are used to assess acid-base balance status and help identify the severity of metabolic acidosis. OBJECTIVES: To explore the association of AG and ACAG with the risk of AKI in AIS patients admitted to the intensive care unit (ICU). MATERIAL AND METHODS: Data of AIS patients in this retrospective cohort study were extracted from the electronic ICU (eICU) databases (2014-2015). The outcome was the occurrence of AKI after ICU admission. The covariates included demographic data, vital signs, comorbidities, laboratory parameters, and medication use. The association of AG and ACAG levels with AKI risk in AIS patients was evaluated using univariate and multivariate logistic regression models with odds ratios (ORs) and 95% confidence intervals (95% CIs). The predictive performance of AG and ACAG for the risk of AKI in AIS patients was assessed with the area under the curve (AUC). To further explore the association of AG and ACAG levels with AKI risk, subgroup analyses were performed according to comorbidities. RESULTS: Of the 1,260 AIS patients, 546 (43%) developed AKI. Elevated AG (OR = 1.73, 95% CI: 1.32-2.29) and ACAG (OR = 1.57, 95% CI: 1.21-2.04) were associated with the risk of AKI in AIS patients. The AUC of ACAG was superior to AG for predicting the risk of AKI (0.581 vs 0.558; p = 0.024). Elevated ACAG levels were associated with the risk of AKI in AIS patients without ischemic heart disease (OR = 1.60, 95% CI: 1.19-2.15), diabetes (OR = 1.58, 95% CI: 1.19-2.10) and hypertension (OR = 1.69, 95% CI: 1.24-2.30). CONCLUSIONS: Albumin corrected anion gap was a better predictor than AG for AKI risk in AIS patients, which may help clinicians identify high-risk patients for AKI.

6.
Sci Rep ; 14(1): 16138, 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-38997399

RESUMEN

Insulin resistance (IR) has a strong association with acute ischemic stroke (AIS) occurrence and poor prognosis of afflicted patients. However, the relation between early neurological deterioration (END) risk and IR in elderly and middle-aged patients remains to be thoroughly studied. Here, we investigated the relationship between four indicators of IR and the risk of END in middle-aged patients patients with AIS. The study retrospectively analyzed 1696 elderly and middle-aged patients having AIS between January 2019 and June 2023. Within 7 days of admission, the patients were then stratified relying upon alternations in the National Institutes of Health Stroke Scale. Subsequently, we employed logistic regression analyses for assessing each index correlation with END on the basis of the tertiles of TyG index (TyGI), triglyceride to high-density lipoprotein ratio (TG/HDL), TyG-BMI, alongside IR metabolic score (METS-IR). These four indicators were significantly heightened in the END group (n = 680) in comparison to the non-END group (n = 1016). When grouping using tertiles, the four aforementioned indicators emerged as independent risk factors for END occurrence, whether or not adjusted for confounding factors. The results revealed a progressive elevation in END occurrence risk with the rise in the tertile of each indicator. Finally, we utilized receiver operating characteristic (ROC) curves for assessing the indicators' predictive power. TyG-BMI, TyGI, TG/HDL, and METS-IRs' area under the curve (AUC) were, respectively, 0.736 (95% CI: 0.712-0.761; P < 0.001), 0. 694 (95% CI: 0.668-0.721; P < 0.001), 0.684 (95% CI: 0.658-0.711; P < 0.001), and 0.722 (95% CI: 0.697-0.747; P < 0.001). IR is associated with END risk in middle-aged AIS patients. TyG-BMI, TyGI, TG/HDL, and METS-IR are independent risk factors of END in elderly and middle-aged AIS patients. Simultaneously, these four IR indicators have significant predictive power for END.


Asunto(s)
Resistencia a la Insulina , Accidente Cerebrovascular Isquémico , Humanos , Masculino , Femenino , Accidente Cerebrovascular Isquémico/sangre , Accidente Cerebrovascular Isquémico/diagnóstico , Anciano , China/epidemiología , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Pronóstico , Triglicéridos/sangre , Curva ROC
7.
Int Immunopharmacol ; 139: 112646, 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-39002520

RESUMEN

Neuroinflammation and neurodegeneration are hallmarks of multiple sclerosis (MS). Bromodomain-containing protein 4 (BRD4), a bromodomain and extra-terminal domain (BET) protein family member, is indispensable for the transcription of pro-inflammatory genes. Therefore, inhibiting BRD4 may be a prospective therapeutic approach for modulating the inflammatory response and regulating the course of MS. dBET1, a newly synthesized proteolysis-targeting chimera (PROTAC), exhibits effectively degrades of BRD4. However, the precise effects of dBET1 on MS require further investigation. Therefore, we assessed the effect of dBET1 in experimental autoimmune encephalomyelitis (EAE), a typical MS experimental model. Our findings revealed that BRD4 is mainly expressed in astrocytes and neurons of the spinal cords, and is up-regulated in the spinal cords of EAE mice. The dBET1 attenuated lipopolysaccharide-induced expression of astrocytic pro-inflammatory mediators and inhibited deleterious molecular activity in astrocytes. Correspondingly, dBET1, used in preventive and therapeutic settings, alleviated the behavioral symptoms in EAE mice, as demonstrated by decreased demyelination, alleviated leukocyte infiltration, reduced microglial and astrocyte activation, and diminished inflammatory mediator levels. In addition, dBET1 corrected the imbalance in peripheral T cells and protected blood-brain barrier integrity in EAE mice. The underlying mechanism involved suppressing the phosphoinositide-3-kinase/protein kinase B, mitogen-activated protein kinase /extracellular signal-regulated kinase, and nuclear factor kappa B pathways. In summary, our data strongly suggests that dBET1 is a promising treatment option for MS.

8.
Am J Med Genet B Neuropsychiatr Genet ; 162B(5): 466-73, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23740716

RESUMEN

We have estimated the prevalence of FMR1 premutation and gray zone CGG repeat expansions in a population-based sample of 19,996 male and female adults in Wisconsin and compared the observed sex ratios of the prevalence of FMR1 CGG premutation and gray zone expansions to theoretical sex ratios. The female premutation prevalence was 1 in 148 and comparable to past research, but the male premutation prevalence of 1 in 290 is somewhat higher than most previous estimates. The female:male premutation prevalence ratio is in line with the theoretically predicted sex ratio. The prevalence of CGG repeats in the gray zone (45-54 repeats) was 1 in 33 females and 1 in 62 males. The prevalence of the "expanded" gray zone (defined here as 41-54 CGG repeats) was 1 in 14 females and 1 in 22 males, leading to a female:male ratio of 1.62 (95% confidence interval 1.39-1.90). This female:male ratio was significantly lower than the expected ratio of 2.0. We examined results from three previously published FMR1 prevalence studies and found similar female:male ratios for CGG repeats in this "expanded" gray zone range (pooled female:male ratio across all four studies 1.66, 95% confidence interval 1.51-1.82). Further research is needed to understand the apparent excess prevalence of males with CGG repeats in this range.


Asunto(s)
Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Razón de Masculinidad , Repeticiones de Trinucleótidos , Adulto , Femenino , Síndrome del Cromosoma X Frágil/epidemiología , Síndrome del Cromosoma X Frágil/genética , Frecuencia de los Genes , Humanos , Masculino , Mutación , Prevalencia , Wisconsin/epidemiología
9.
Front Aging Neurosci ; 14: 1056312, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36506471

RESUMEN

Background: To date, the pathogenesis of Alzheimer's disease is still not fully elucidated. Much evidence suggests that Ferroptosis plays a crucial role in the pathogenesis of AD, but little is known about its molecular immunological mechanisms. Therefore, this study aims to comprehensively analyse and explore the molecular mechanisms and immunological features of Ferroptosis-related genes in the pathogenesis of AD. Materials and methods: We obtained the brain tissue dataset for AD from the GEO database and downloaded the Ferroptosis-related gene set from FerrDb for analysis. The most relevant Hub genes for AD were obtained using two machine learning algorithms (Least absolute shrinkage and selection operator (LASSO) and multiple support vector machine recursive feature elimination (mSVM-RFE)). The study of the Hub gene was divided into two parts. In the first part, AD patients were genotyped by unsupervised cluster analysis, and the different clusters' immune characteristics were analysed. A PCA approach was used to quantify the FRGscore. In the second part: we elucidate the biological functions involved in the Hub genes and their role in the immune microenvironment by integrating algorithms (GSEA, GSVA and CIBERSORT). Analysis of Hub gene-based drug regulatory networks and mRNA-miRNA-lncRNA regulatory networks using Cytoscape. Hub genes were further analysed using logistic regression models. Results: Based on two machine learning algorithms, we obtained a total of 10 Hub genes. Unsupervised clustering successfully identified two different clusters, and immune infiltration analysis showed a significantly higher degree of immune infiltration in type A than in type B, indicating that type A may be at the peak of AD neuroinflammation. Secondly, a Hub gene-based Gene-Drug regulatory network and a ceRNA regulatory network were successfully constructed. Finally, a logistic regression algorithm-based AD diagnosis model and Nomogram diagram were developed. Conclusion: Our study provides new insights into the role of Ferroptosis-related molecular patterns and immune mechanisms in AD, as well as providing a theoretical basis for the addition of diagnostic markers for AD.

10.
Mol Med Rep ; 15(6): 4286-4290, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28440512

RESUMEN

Astemizole has gained attention as an antineoplastic drug that targets important ion channels. The present study aimed to investigate the protective effects of astemizole against hydrogen peroxide (H2O2)­induced oxidative damage to human umbilical vein endothelial cells (HUVECs). HUVECs were pretreated with astemizole (0.5 and 1 µM) for 12 h, then exposed to H2O2 (200 µM) for 12 h. Cell viability was measured using the MTT assay. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH­Px), reactive oxygen species (ROS) and apoptotic percentage were determined. Additionally, the protein expression of p53, p21Cip1/Waf1 and p16INK4a was measured by western blot analysis The results demonstrated that astemizole (0.5­1 µM) was able to significantly restore the viability of HUVECs under oxidative stress and scavenge intracellular ROS induced by H2O2. Astemizole also suppressed the production of lipid peroxides, such as MDA, and restored the activities of endogenous antioxidants, including SOD and GSH­Px, indicating that cell apoptosis may be inhibited. In addition, astemizole significantly increased p53, p21Cip1/Waf1 and p16INK4a protein expression. In conclusion, astemizole effectively protected endothelial cells against oxidative stress induced by H2O2, a function that may involve ROS/p53/p21Cip1/Waf1/ p16INK4a signaling pathways. The present study therefore served as a preliminary investigation into the ROS­protective effects of astemizole, and may pave the way for future studies into the development of this compound as a novel therapy for atherosclerosis.


Asunto(s)
Astemizol/farmacología , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Peróxido de Hidrógeno/farmacología , Sustancias Protectoras/farmacología , Transducción de Señal/efectos de los fármacos , Proteína p53 Supresora de Tumor/metabolismo , Antioxidantes/metabolismo , Apoptosis/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Glutatión Peroxidasa/metabolismo , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Malondialdehído/metabolismo , Óxido Nítrico/metabolismo , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/metabolismo
11.
Oncol Lett ; 13(4): 2418-2424, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28454413

RESUMEN

Ovarian carcinoma is a common malignant disease worldwide with a poor therapeutic response. The present study investigated the effects of Na7CrCuW11O39.16H2O (CrCuW11) on ovarian cancer cell growth and investigated the mechanisms underlying its actions. The effects of CrCuW11 on cell viability and apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, acridine orange/ethidium bromide staining and electron microscopy in human ovarian cancer SKOV3 cells. The expression of bcl-2-like protein 4 (Bax), B-cell lymphoma 2 (Bcl-2), cytochrome c, phosphorylated (p)-p38 and p38 was determined by western blot analysis. Caspase-3 activity was measured by caspase-3 activity kit. CrCuW11 concentrations of 1.87×10-3 mol. l-1 at 12 h reduced viability induced apoptosis in SKOV3 cells in a concentration-and time-dependent manner. Forced expression of CrCuW11 upregulated the expression of certain proteins (Bax, cytochrome c, and p-p38), and downregulated Bcl-2 protein expression. Furthermore, CrCuW11 also enhanced caspase-3 activity. The p38 inhibitor SB203580 was able to inhibit the activity of CrCuW11. Caspase-3 and p38 signaling pathways were associated with CrCuW11-regulated multiple targets involved in SKOV3 cell proliferation. Therefore, the results of the present study indicated that CrCuW11 may be used as a novel clinical drug for the treatment of ovarian cancer.

12.
Genetics ; 202(4): 1563-74, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26837753

RESUMEN

Studies of the genetic loci that contribute to variation in gene expression frequently identify loci with broad effects on gene expression: expression quantitative trait locus hotspots. We describe a set of exploratory graphical methods as well as a formal likelihood-based test for assessing whether a given hotspot is due to one or multiple polymorphisms. We first look at the pattern of effects of the locus on the expression traits that map to the locus: the direction of the effects and the degree of dominance. A second technique is to focus on the individuals that exhibit no recombination event in the region, apply dimensionality reduction (e.g., with linear discriminant analysis), and compare the phenotype distribution in the nonrecombinant individuals to that in the recombinant individuals: if the recombinant individuals display a different expression pattern than the nonrecombinant individuals, this indicates the presence of multiple causal polymorphisms. In the formal likelihood-based test, we compare a two-locus model, with each expression trait affected by one or the other locus, to a single-locus model. We apply our methods to a large mouse intercross with gene expression microarray data on six tissues.


Asunto(s)
Expresión Génica , Modelos Genéticos , Sitios de Carácter Cuantitativo , Animales , Mapeo Cromosómico , Simulación por Computador , Cruzamientos Genéticos , Endogamia , Escala de Lod , Ratones , Análisis Multivariante , Carácter Cuantitativo Heredable , Recombinación Genética
13.
Cancer Inform ; 13(Suppl 7): 123-31, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26609213

RESUMEN

In this paper, we propose a novel multivariate component-wise boosting method for fitting multivariate response regression models under the high-dimension, low sample size setting. Our method is motivated by modeling the association among different biological molecules based on multiple types of high-dimensional genomic data. Particularly, we are interested in two applications: studying the influence of DNA copy number alterations on RNA transcript levels and investigating the association between DNA methylation and gene expression. For this purpose, we model the dependence of the RNA expression levels on DNA copy number alterations and the dependence of gene expression on DNA methylation through multivariate regression models and utilize boosting-type method to handle the high dimensionality as well as model the possible nonlinear associations. The performance of the proposed method is demonstrated through simulation studies. Finally, our multivariate boosting method is applied to two breast cancer studies.

14.
Genetics ; 201(3): 1253-62, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26385979

RESUMEN

We surveyed gene expression in six tissues in an F2 intercross between mouse strains C57BL/6J (abbreviated B6) and BTBR T(+) tf/J (abbreviated BTBR) made genetically obese with the Leptin(ob) mutation. We identified a number of expression quantitative trait loci (eQTL) affecting the expression of numerous genes distal to the locus, called trans-eQTL hotspots. Some of these trans-eQTL hotspots showed effects in multiple tissues, whereas some were specific to a single tissue. An unusually large number of transcripts (∼8% of genes) mapped in trans to a hotspot on chromosome 6, specifically in pancreatic islets. By considering the first two principal components of the expression of genes mapping to this region, we were able to convert the multivariate phenotype into a simple Mendelian trait. Fine mapping the locus by traditional methods reduced the QTL interval to a 298-kb region containing only three genes, including Slco1a6, one member of a large family of organic anion transporters. Direct genomic sequencing of all Slco1a6 exons identified a nonsynonymous coding SNP that converts a highly conserved proline residue at amino acid position 564 to serine. Molecular modeling suggests that Pro564 faces an aqueous pore within this 12-transmembrane domain-spanning protein. When transiently overexpressed in HEK293 cells, BTBR organic anion transporting polypeptide (OATP)1A6-mediated cellular uptake of the bile acid taurocholic acid (TCA) was enhanced compared to B6 OATP1A6. Our results suggest that genetic variation in Slco1a6 leads to altered transport of TCA (and potentially other bile acids) by pancreatic islets, resulting in broad gene regulation.


Asunto(s)
Islotes Pancreáticos/metabolismo , Transportadores de Anión Orgánico/genética , Sustitución de Aminoácidos , Animales , Proteínas Portadoras , Regulación de la Expresión Génica , Células HEK293 , Humanos , Glicoproteínas de Membrana , Ratones , Ratones Endogámicos C57BL , Sitios de Carácter Cuantitativo , Ácido Taurocólico/metabolismo
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